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Hydra, what’s the big deal anyway?
RemObjects Hydra is a product I have used for years in concert with Delphi, and like most developers that come into contact with RemObjects products – once the full scope of the components hit you, you never want to go back to not using Hydra in your applications.
Note: It’s easy to dismiss Hydra as a “Delphi product”, but Hydra for .Net and Java does the exact same thing, namely let you mix and match modules from different languages in your programs. So if you are a C# developer looking for ways to incorporate Java, Delphi, Elements or Freepascal components in your application, then keep reading.
But let’s start with what Hydra can do for Delphi developers.
What is Hydra anyways?
Hydra is a component package for Delphi, Freepascal, .Net and Java that takes plugins to a whole new level. Now bear with me for a second, because these plugins is in a completely different league from anything you have used in the past.
In short, Hydra allows you to wrap code and components from other languages, and use them from Delphi or Lazarus. There are thousands of really amazing components for the .Net and Java platforms, and Hydra allows you compile those into modules (or “plugins” if you prefer that); modules that can then be used in your applications like they were native components.
Hydra, here using a C# component in a Delphi application
But it doesn’t stop there; you can also mix VCL and FMX modules in the same application. This is extremely powerful since it offers a clear path to modernizing your codebase gradually rather than doing a time consuming and costly re-write.
So if you want to move your aging VCL codebase to Firemonkey, but the cost of having to re-write all your forms and business logic for FMX would break your budget -that’s where Hydra gives you a second option: namely that you can continue to use your VCL code from FMX and refactor the application in your own tempo and with minimal financial impact.
The best of all worlds
Not long ago RemObjects added support for Lazarus (Freepascal) to the mix, which once again opens a whole new ecosystem that Delphi, C# and Java developers can benefit from. Delphi has a lot of really cool components, but Lazarus have components that are not always available for Delphi. There are some really good developers in the Freepascal community, and you will find hundreds of components and classes (if not thousands) that are open-source; For example, Lazarus has a branch of Synedit that is much more evolved and polished than the fork available for Delphi. And with Hydra you can compile that into a module / plugin and use it in your Delphi applications.
This is also true for Java and C# developers. Some of the components available for native languages might not have similar functionality in the .Net world, and by using Hydra you can tap into the wealth that native languages have to offer.
As a Delphi or Freepascal developer, perhaps you have seen some of the fancy grids C# and Java coders enjoy? Developer Express have some of the coolest components available for any platform, but their focus is more on .Net these days than Delphi. They do maintain the control packages they have, but compared to the amount of development done for C# their Delphi offerings are abysmal. So with Hydra you can tap into the .Net side of things and use the latest components and libraries in your Delphi applications.
Financial savings
One of coolest features of Hydra, is that you can use it across Delphi versions. This has helped me leverage the price-tag of updating to the latest Delphi.
It’s easy to forget that whenever you update Delphi, you also need to update the components you have bought. This was one of the reasons I was reluctant to upgrade my Delphi license until Embarcadero released Delphi 10.2. Because I had thousands of dollars invested in components – and updating all my licenses would cost a small fortune.
So to get around this, I put the components into a Hydra module and compiled that using my older Delphi. And then i simply used those modules from my new Delphi installation. This way I was able to cut cost by thousands of dollars and enjoy the latest Delphi.
Using Firemonkey controls under VCL is easy with Hydra
A couple of years back I also took the time to wrap a ton of older components that work fine but are no longer maintained or sold. I used an older version of Delphi to get these components into a Hydra module – and I can now use those with Delphi 10.3 (!). In my case there was a component-set for working closely with Active Directory that I have used in a customer’s project (and much faster than having to go the route via SQL). The company that made these don’t exist any more, and I have no source-code for the components.
The only way I could have used these without Hydra, would be to compile them into a .dll file and painstakingly export every single method (or use COM+ to cross the 32-bit / 64-bit barrier), which would have taken me a week since we are talking a large body of quality code. With Hydra i was able to wrap the whole thing in less than an hour.
I’m not advocating that people stop updating their components. But I am very thankful for the opportunity to delay having to update my entire component stack just to enjoy a modern version of Delphi.
Hydra gives me that opportunity, which means I can upgrade when my wallet allows it.
Building better applications
There is also another side to Hydra, namely that it allows you to design applications in a modular way. If you have the luxury of starting a brand new project and use Hydra from day one, you can isolate each part of your application as a module. Avoiding the trap of monolithic applications.
Hydra for .Net allows you to use Delphi, Java and FPC modules under C#
This way of working has great impact on how you maintain your software, and consequently how you issue hotfixes and updates. If you have isolated each key part of your application as separate modules, you don’t need to ship a full build every time.
This also safeguards you from having all your eggs in one basket. If you have isolated each form (for example) as separate modules, there is nothing stopping you from rewriting some of these forms in another language – or cross the VCL and FMX barrier. You have to admit that being able to use the latest components from Developer Express is pretty cool. There is not a shadow of a doubt that Developer-Express makes the best damn components around for any platform. There are many grids for Delphi, but they cant hold a candle to the latest and greatest from Developer Express.
Why can’t I just use packages?
If you are thinking “hey, this sounds exactly like packages, why should I buy Hydra when packages does the exact same thing?“. Actually that’s not how packages work for Delphi.
Delphi packages are cool, but they are also severely limited. One of the reasons you have to update your components whenever you buy a newer version of Delphi, is because packages are not backwards compatible.
Delphi packages are great, but severely limited
A Delphi package must be compiled with the same RTL as the host (your program), and version information and RTTI must match. This is because packages use the same RTL and more importantly, the same memory manager.
Hydra modules are not packages. They are clean and lean library files (*.dll files) that includes whatever RTL you compiled them with. In other words, you can safely load a Hydra module compiled with Delphi 7, into a Delphi 10.3 application without having to re-compile.
Once you start to work with Hydra, you gradually build up modules of functionality that you can recycle in the future. In many ways Hydra is a whole new take on components and RAD. This is how Delphi packages and libraries should have been.
Without saying anything bad about Delphi, because Delphi is a system that I love very much; but having to update your entire component stack just to use the latest Delphi, is sadly one of the factors that have led developers to abandon the platform. If you have USD 10.000 in dependencies, having to pay that as well as buying Delphi can be difficult to justify; especially when comparing with other languages and ecosystems.
For me, Hydra has been a tremendous boon for Delphi. It has allowed me to keep current with Delphi and all it’s many new features, without losing the money I have already invested in components packages.
If you are looking for something to bring your product to the next level, then I urge you to spend a few hours with Hydra. The documentation is exceptional, the features and benefits are outstanding — and you will wonder how you ever managed to work without them.
External resources
Disclaimer: I am not a salesman by any stretch of the imagination. I realize that promoting a product made by the company you work for might come across as a sales pitch; but that’s just it: I started to work for RemObjects for a reason. And that reason is that I have used their products since they came on the market. I have worked with these components long before I started working at RemObjects.
.NetRocks, you made my day!
A popular website for .Net developers is called dot-net-rocks. This is an interesting site that has been going for a while now; well worth the visit if you do work with the .Net framework via RemObjects Elements, VS or Mono.
Now it turns out that the guys over at dot–net-rocks just did an episode on their podcast where they open by labeling me as a “raving lunatic” (I clearly have my moments); which I find absolutely hilarious, but not for the same reasons as them.
Long story short: They are doing a podcast on how to migrate legacy Delphi applications to C#, and in that context they somehow tracked down an article I posted way back in 2016, which was meant as a satire piece. Now don’t get me wrong, there are serious points in the article, like how the .Net framework was modeled on the Delphi VCL, and how the concepts around CLR and JIT were researched at Borland; but the tone of the whole thing, the “larger than life” claims etc. was meant to demonstrate just how some .Net developers behave when faced with alternative eco-systems. Having managed some 16+ usergroups for Delphi, C#, JavaScript (a total of six languages) on Facebook for close to 15 years, as well as working for Embarcadero that makes Delphi -I speak from experience.
It might be news to these guys that large companies around Europe is still using Delphi, modern Delphi, and that Object Pascal as a language scores well on the Tiobi index of popular programming languages. And no amount of echo-chamber mentality is going to change that fact. Heck, as late as 2018 and The Walt Disney Company wanted to replace C# with Delphi, because it turns out that bytecodes and embedded tech is not the best combination (cpu spikes when the GC kicks in, no real-time interrupt handling possible, GPIO delays, the list goes on).
I mean, the post i made back in 2016 is such obvious, low-hanging fruit for a show their size to pound on. You have this massive show that takes on a single, albeit ranting (and probably a bit of a lunatic if I don’t get my coffee) coder’s post. Underlying in the process how little they know about the object pascal community at large. They just demonstrated my point in bold, italic and underline 😀
Look before you shoot
DotNetRocks is either oblivious that Delphi still have millions of users around the world, or that Pascal is in fact available for .Net (which is a bit worrying since .Net is supposed to be their game). The alternative is that the facts I listed hit a little too close to home. I’ll leave it up to the reader to decide. Microsoft has lost at least 10 Universities around Europe to Delphi in 2018 that I know of, two of them Norwegian where I was personally involved in the license sales. While only speculation, I do find the timing for their podcast and focus on me in particular to be, “curious”.
And for the record, the most obvious solution when faced with “that legacy Delphi project”, is to just go and buy a modern version of Delphi. DotNetRocks delivered a perfect example of that very arrogance my 2016 post was designed to convey; namely that “brogrammers” often act like Delphi 7 was the last Delphi. They also resorted to lies to sell their points: I never said that Anders was dogged for creating Delphi. Quite the opposite. I simply underlined that by ridiculing Delphi in one hand, and praising it’s author with the other – you are indirectly (and paradoxically) invalidating half his career. Anders is an awesome developer, but why exclude how he evolved his skills? Ofcourse Ander’s products will have his architectural signature on them.
Not once did they mention Embarcadero or the fact that Delphi has been aggressively developed since Borland kicked the bucket. Probably hoping that undermining the messenger will somehow invalidate the message.
Porting Delphi to C# manually? Ok.. why not install Elements and just compile it into an assembly? You don’t even have to leave Visual Studio
Also, such an odd podcast for professional developers to run with. I mean, who the hell converts a Delphi project to C# manually? It’s like listening to a graphics artist that dont know that Photoshop and Illustrator are the de-facto tools to use. How is that even possible? A website dedicated to .Net, yet with no insight into the languages that run on the CLR? Wow.
If you want to port something from Delphi to .Net, you don’t sit down and manually convert stuff. You use proper tools like Elements from RemObjects; This gives you Object-Pascal for .Net (so a lot of code will compile just fine with only minor changes). Elements also ships with source-conversion tools, so once you have it running under Oxygene Pascal (the dialect is called Oxygene) you either just use the assemblies — or convert the Pascal code to C# through a tool called an Oxidizer.
The most obvious solution is to just upgrade to a Delphi version from this century
The other solution is to use Hydra, also a RemObjects product. They can then compile the Delphi code into a library (including visual parts like forms and frames), and simply use that as any other assembly from within C#. This allows you to gradually phase out older parts without breaking the product. You can also use C# assemblies from Delphi with Hydra.
So by all means, call me what you like. You have only proved my point so far. You clearly have zero insight into the predominant Object-Pascal eco-systems, you clearly don’t know the tools developers use to interop between arcetypical and contextual languages — and instead of fact checking some of the points I made, dry humor notwithstanding, you just reacted like brogrammers do.
Well, It’s been weeks since I laughed this hard 😀 You really need to check before you pick someone to verbally abuse on the first date, because you might just bite yourself in the arse here he he
Cheers
Why move to Windows 10?
When it comes to Windows editions, Windows 7 is probably the most successful operating-system Microsoft has ever released. When it hit stores back in October of 2009, it replaced Windows Vista (Longhorn) which, truth be told, caused more problems than it solved. The issues surrounding Vista were catastrophic for many reasons, but they were especially severe for developers. I remember buying a brand new laptop with Vista pre-installed, but in less than a week I rolled back to Windows XP.
In retrospect, Vista was perhaps not as bad as it’s reputation would have it. I honestly feel it’s a very misunderstood edition of Windows, one that brought features common to the NT family into the mainstream. But back then people were still unfamiliar with what exactly that meant; things like “roaming profiles” was alien to users and developers with no background in networking. In my case Vista came at a juncture where I had two product releases on my hand. Time was of the essence, and spending days refactoring my code for the changes could not have come at a worse moment.
Be this as it may, the rejection of Vista forced Microsoft to replace it with something better. Vista was supposed to have a 10 year life-cycle, but Microsoft put Vista out of its misery in 3 years.
Windows 7 retirement plan
Windows 7 has been a wonderful system to work with. I can honestly say that with exception of Windows 10, it’s been the best operating system I have ever used. And i include OS X and Ubuntu in that equation. But as great as it was, Windows 7 is now 10 years old; an eternity in the software business. The needs of consumers and developers are radically different today, and with Windows 10 available as a free upgrade – it’s time to let the system go.
Microsoft actually ended mainstream support back in January of 2015 (!), but due to its popularity and massive adoption, they decided to extend support a few more years. This means that Windows 7, although practically retro in computing terms, still receives driver updates and security patches. But that is about to change sooner than you think.
Come next January (read: over xmas) and Windows 7 has an appointment with the gallows; something that will affect laptops, servers and desktop systems alike. This means there will be no more security patches, no more feature updates and no new virus definitions for Windows Defender. In other words January 14 2020 is the day Microsoft take Windows 7 off life-support.
This retirement also affects tablets, so if you have a Windows 7 based Surface, the time has come to jump ship and get Windows 10 installed. The same is true for Windows 7 Enterprise – it’s already obsolete by half a decade.
Some have stated that the embedded version of Windows 7, used primarily in custom-made products like ATMs, POS and kiosk type products, somehow avoids this retirement; but that’s just it – retirement truly means retirement. January 14 2020 really is the day Microsoft puts Windows 7 in the ground; be it laptop, server, desktop or surface.
The king is dead, long live the king
You might be wondering, since Windows 7 is still so popular, why would Microsoft seek to replace it? Well there are many reasons. First of all Windows 7 is based on the old NT kernel, which by today’s standard is a dinosaur compared to competing operating-systems. NT was constructed around a security scheme that has served humanity well, but it’s poorly equipped to deal with modern threats. Windows 7 also has a considerably larger memory footprint compared to Windows 10 – not to mention that Windows 10 has been optimized from scratch for better performance on all supported devices. So it’s never really been a question of why, but rather when and at which cost.
Windows 10 comes in many shapes and sizes
You also have to factor in that Windows 10 introduces a host of new features that is unique to that OS. Things like support for touch interfaces (both display and navigation devices) is one of them, but developers will be more affected by the new application model (UWP) and UI framework. Truth be told, UWP was first introduced in Windows 8 as a part of Microsoft’s plan to streamline all versions of their OS (tablet, mobile, desktop and server). The promise of UWP is that, if you follow the guidelines and stick to the APIs – the same application can run on all variations of the same OS; regardless of CPU even (more about that below).
Since this was introduced Microsoft sadly dropped out of the smartphone OS business though. Their Windows for mobile never gained the recognition it deserved, and they retired it in favor of Android. Personally i loved their phones; they somehow managed to take the best features from both Apple iOS and Android, and combine them intuitively and elegantly. Not to mention that they cost 40% of what an iPhone of Samsung Galaxy sold for.
Windows 10 is also the first OS from Microsoft that treats XBox as a first-class citizen, so developing titles for XBox has become easier. DirectX now aims at delivering console level experience for laptop and desktop computers; it’s pretty much been refactored from scratch, with aggressive and radical optimization (read: hand written assembly) to get every last drop of performance out of the hardware.
Unlike previous editions of DirectX, Microsoft has toned down the amount of insulation between your code and the actual hardware. DirectX was always padded left and right with interfaces and abstractions, making raw access to GPU resources impossible (or at least, impractical). Thankfully Microsoft has realized that they took this too far, and trimmed the insulation layers accordingly; meaning that developers can now access resources en-par with AMD Mantle, Apple Metal and Vulcan (Factoid: Vulcan is a replacement for OpenGL. OpenGL originated with Silicon Graphics machines, a graphics workstation that was hugely popular back in the 90s and early 2k’s).
WinRT, ARM and the beyond
While developers who focus on business applications could care less about DirectX and multimedia, the underlying changes to the Windows 10 core are of such a magnitude that all avenues of development will be affected. Some of the UI changes are profoundly linked to the work that makes Windows 10 unique – and Microsoft has made it perfectly clear that all future endeavors is built on the Windows 10 baseline.
Windows is moving to ARM, and Windows 10 technology is the foundation
Besides purely technical changes, access to the Microsoft Store is one of the features that have a more immediate, financial effect on software development. Marco Cantu actually blogged about this back in 2016, regarding how you can use WDB (Windows Desktop Bridge, a.k.a “project Centennial”) to publish Firemonkey applications to Microsoft store. I mean, any modern developer who makes a living from selling software, having their products available through official channels is pretty essential. And that excludes Windows 7 by default.
And last but not least, there is WinRT, short for Windows Runtime, a sand boxed version of windows that allows applications to be deployed to both x86 and ARM. WinRT involves x86 emulation on ARM SoCs (system on a chip), meaning that you will be able to run applications compiled for x86 on Microsoft’s upcoming Windows for ARM release. But performance wise emulation will obviously not deliver the same level of performance as native ARM code. The emulation layer is meant as an intermediate solution, allowing developers time to evolve compilers that can target ARM directly.
I probably don’t have to outline the business opportunities Windows on ARM represent.
Market adoption
If the features and promise of Windows 10 is not enough to convince you to update immediately, consider the following: There are more than 1 billion Windows users in the world. Windows 7 presently holds 37% of the global market (with Windows 10 at 43%), which means that hundreds of millions of computers will be affected by the now immanent retirement plan.
ARM is still a hardware platform companies can afford to postpone, but with both Apple and Microsoft being open about their move to ARM in the near future, the risk for developers being left behind is very real. And having to deal with the cost of refactoring your entire portfolio over something as trivial as an update, well – I’m sure you see my point.
There really is zero strategic advantage in sticking with the lowest common denominator, which in this case is the stock WinAPI that has defined Windows since the nineties. Especially not when upgrading to Windows 10 is free of charge.
Reflections
From a personal point of view, I cannot imagine being a developer in 2019 and relying on an operating-system that is retired. I must admit that I do own virtual machines where Windows 7 is used, but those are not instances where I do software development; I use them primarily for stress testing software running in other VMWare instances, which conceptually is not a problem.
Microsoft is still offering a free upgrade plan for Windows 7 users. In other words there is no financial loss in updating your development machines, be they physical or virtual.
I look forward to Microsoft’s next phase, where virtual reality and augmented reality technology is implemented more closely for all supported hardware platforms. As for changes that affect desktop business applications, have a look at the following links:
Using multiple languages is the same project
Most compilers can only handle a single syntax for any project, but the Elements compiler from RemObjects deals with 5 (five!) different languages -even within the same project. That’s pretty awesome and opens up for some considerable savings.
I mean, it’s not always easy to find developers for a single language, but when you can approach your codebase from C#, Java, Go, Swift and Oxygene (object pascal) at the same time (inside the same project even!), you suddenly have some options. Especially since you can pick exotic targets like WebAssembly. Or what about compiling Java to .net bytecodes? Or using the VCL from C#? It’s pretty awesome stuff!
Check out Marc Hoffmans article on the Elements compiler toolchain and how you can mix and match between languages, picking the best from each — while still compiling to a single binary of llvm optimized code:
Click on the picture to be redirected
Check out RemObjects Remoting SDK
RemObjects Remoting SDK is one of those component packages that have become more than the sum of it’s part. Just like project Jedi has become standard equipment almost, Remoting SDK is a system that all Delphi and Freepascal developers should have in their toolbox.
In this article I’m going to present the SDK in broad strokes; from a viewpoint of someone who haven’t used the SDK before. There are still a large number of Delphi developers that don’t know it even exists – hopefully this post will shed some light on why the system is worth every penny and what it can do for you.
I should also add, that this is a personal blog. This is not an official RemObjects presentation, but a piece written by me based on my subjective experience and notions. We have a lot of running dialog at Delphi Developer on Facebook, so if I read overly harsh on a subject, that is my personal view as a Delphi Developer.
Stop re-inventing the wheel
Delphi has always been a great tool for writing system services. It has accumulated a vast ecosystem of non-visual components over the years, both commercial and non-commercial, and this allows developers to quickly aggregate and expose complex behavior — everything from graphics processing to databases, file processing to networking.
The challenge for Delphi is that writing large composite systems, where you have more than a single service doing work in concert, is not factored into the RTL or project type. Delphi provides a bare-bone project type for system services, and that’s it. Depending on how you look at it, it’s either a blessing or a curse. You essentially start on C level.
So fundamental things like IPC (inter process communication) is something you have to deal with yourself. If you want multi-tenancy that is likewise not supported out of the box. And all of this is before we venture into protocol standards, message formats and async vs synchronous execution.
The idea behind Remoting SDK is to get away from this style of low-level hacking. Without sounding negative, it provides the missing pieces that Delphi lacks, including the stuff that C# developers enjoy under .net (and then some). So if you are a Delphi developer who look over at C# with smudge of envy, then you are going to love Remoting SDK.
Say goodbye to boilerplate mistakes
Writing distributed servers and services is boring work. For each function you expose, you have to define the parameters and data-types in a portable way, then you have to implement the code that represents the exposed function and finally the interface itself that can be consumed by clients. The latter must be defined in a way that works with other languages too, not just Delphi. So while server tech in it’s essential form is quite simple, it’s the infrastructure that sets the stage of how quickly you can apply improvements and adapt to change.
For example, let’s say you have implemented a wonderful new service. It exposes 60 awesome functions that your customers can consume in their own work. The amount of boilerplate code for 60 distributed functions, especially if you operate with composite data types, is horrendous. It is a nightmare to manage and opens up for sloppy, unnecessary mistakes.
After you install Remoting SDK, the service designer becomes a part of the IDE
This is where Remoting SDK truly shines. When you install the software, it integrates it’s editors and wizards closely with the Delphi IDE. It adds a ton of new project types, components and whatnot – but the most important feature is without a doubt the service designer.
Start the service-designer in any server or service project and you can edit the methods, data types and interfaces your system expose to the world
As the name implies, the service designer allows you to visually define your services. Adding a new function is a simple click, the same goes for datatypes and structures (record types). These datatypes are exposed too and can be consumed from any modern language. So a service you make in Delphi can be used from C#, C/C++, Java, Oxygene, Swift (and visa-versa).
Auto generated code
A service designer is all good and well I hear you say, but what about that boilerplate code? Well Remoting SDK takes care of that too (kinda the point). Whenever you edit your services, the designer will auto-generate a new interface unit for you. This contains the classes and definitions that describe your service. It will also generate an implementation unit, with empty functions; you just need to fill in the blanks.
The designer is also smart enough not to remove code. So if you go in and change something, it won’t just delete the older implementation procedure. Only the params and names will be changed if you have already written some code.
Having changed a service, hitting F9 re-generates the interface code automatically. Your only job is to fill in the code for each method in the implementation units. The SDK takes care of everything else for you
The service information, including the type information, is stored in a special file format called “rodl”. This format is very close to Microsoft WSDL format, but it holds more information. It’s important to underline that you can import the service directly from your servers (optional naturally) as WSDL. So if you want to consume a Remoting SDK service using Delphi’s ordinary RIO components, that is not a problem. Visual Studio likewise imports and consumes services – so Remoting SDK behaves identical regardless of platform or language used.
Remoting SDK is not just for Delphi, just to be clear on that. If you are presently using both Delphi and C# (which is a common situation), you can buy a license for both C# and Delphi and use whatever language you feel is best for a particular task or service. You can even get Remoting SDK for Javascript and call your service-stack directly from your website if you like. So there are a lot of options for leveraging the technology.
Transport is not content
OK so Remoting SDK makes it easy to define distributed services and servers. But what about communication? Are we boxed into RemObjects way of doing things?
The remoting framework comes with a ton of components, divided into 3 primary groups:
- Servers
- Channels (clients)
- Messages
The reason for this distinction is simple: the ability to transport data, is never the same as the ability to describe data. For example, a message is always connected to a standard. It’s job is ultimately to serialize (represent) and de-serialize data according to a format. The server’s job is to receive a request and send a response. So these concepts are neatly decoupled for maximum agility.
As of writing the SDK offers the following message formats:
- Binary
- Post
- SOAP
- JSON
If you are exposing a service that will be consumed from JavaScript, throwing in a TROJSONMessage component is the way to go. If you expect messages to be posted from your website using ordinary web forms, then TROPostMessage is a perfect match. If you want XML then TROSOAPMessage rocks, and if you want fast, binary messages – well then there is TROBinaryMessage.
What you must understand is that you don’t have to pick just one! You can drop all 4 of these message formats and hook them up to your server or channel. The SDK is smart enough to recognize the format and use the correct component for serialization. So creating a distributed service that can be consumed from all major platforms is a matter of dropping components and setting a property.
If you double-click on a server or channel, you can link message components with a simple click. No messy code snippets in sight.
Multi-tenancy out of the box
With the release of Rad-Server as a part of Delphi, people have started to ask what exactly multi-tenancy is and why it matters. I have to be honest and say that yes, it does matter if you are creating a service stack where you want to isolate the logic for each customer in compartments – but the idea that this is somehow new or unique is not the case. Remoting SDK have given users multi-tenancy support for 15+ years, which is also why I haven’t been too enthusiastic with Rad-Server.
Now don’t get me wrong, I don’t have an axe to grind with Rad-Server. The only reason I mention it is because people have asked how i feel about it. The tech itself is absolutely welcome, but it’s the licensing and throwing Interbase in there that rubs me the wrong way. If it could run on SQLite3 and was free with Enterprise I would have felt different about it.
There are various models for multi-tenancy, but they revolve around the same principles
To get back on topic: multi-tenancy means that you can dynamically load services and expose them on demand. You can look at it as a form of plugin functionality. The idea in Rad-Server is that you can isolate a customer’s service in a separate package – and then load the package into your server whenever you need it.
Some of the components that ship with the system
The reason I dislike Rad-Server in this respect, is because they force you to compile with packages. So if you want to write a Rad-Server system, you have to compile your entire project as package-based, and ship a ton of .dpk files with your system. Packages is not wrong or bad per-se, but they open your system up on a fundamental level. There is nothing stopping a customer from rolling his own spoof package and potentially bypass your security.
There is also an issue with un-loading a package, where right now the package remains in memory. This means that hot-swapping packages without killing the server wont work.
Rad-Server is also hardcoded to use Interbase, which suddenly bring in licensing issues that rubs people the wrong way. Considering the price of Delphi in 2019, Rad-Server stands out as a bit of an oddity. And hardcoding a database into it, with the licensing issues that brings -just rendered the whole system mute for me. Why should I pay more to get less? Especially when I have been using multi-tenancy with RemObjects for some 15 years?
With Remoting SDK you have something called DLL servers, which does the exact same thing – but using ordinary DLL files (not packages!). You don’t have to compile your system with packages, and it takes just one line of code to make your main dispatcher aware of the loaded service.
This actually works so well that I use Remoting SDK as my primary “plugin” system. Even when I write ordinary desktop applications that has nothing to do with servers or services – I always try to compartmentalize features that could be replaced in the future.
For example, I’m a huge fan of ElevateDB, which is a native Delphi database engine that compiles directly into your executable. By isolating that inside a DLL as a service, my application is now engine agnostic – and I get a break from buying a truck load of components every time Delphi is updated.
Saving money
The thing about DLL services, is that you can save a lot of money. I’m actually using an ElevateDB license that was for Delphi 2007. I compiled the engine using D2007 into a DLL service — and then I consume that DLL from my more modern Delphi editions. I have no problem supporting or paying for components, that is right and fair, but having to buy new licenses for every single component each time Delphi is updated? This is unheard of in other languages, and I would rather ditch the platform all together than forking out $10k ever time I update.
A DLL server can be used for many things if you are creative about it
While we are on the subject – Hydra is another great money saver. It allows you to use .net and Java libraries (both visual and non-visual) with Delphi. With Hydra you can design something in .net, compile it into a DLL file, and then use that from Delphi.
But — you can also compile things from Delphi, and use it in newer versions of Delphi. Im not forking out for a Developer Express update just to use what I have already paid for in the latest Delphi. I have one license, I compile the forms and components into a Hydra Module — and then use it from newer Delphi editions.
Hydra, which is a separate product, allows you to stuff visual components and forms inside a vanilla DLL. It allows cross language use, so you can finally use Java and .net components inside your Delphi application
Bonjour support
Another feature I love is the zero configuration support. This is one of those things that you often forget, but that suddenly becomes important once you deploy a service stack on cluster level.
Remoting SDK comes with support for Apple Bonjour, so if you want to use that functionality you have to install the Bonjour library from Apple. Once installed on your host machines, your RemObjects services can find each other.
ZeroConfig is not that hard to code manually. You can roll your own using UDP or vanilla messages. But getting service discovery right can be fiddly. One thing is broadcasting an UDP message saying “here I am”, it’s something else entirely to allow service discovery on cluster level.
If Bonjour is not your cup of tea, the SDK provides a second option, which is RemObjects own zero-config hub. You can dig into the documentation to find out more about this.
What about that IPC stuff you mentioned?
I mentioned IPC (inter process communication) at the beginning here, which is a must have if you are making a service stack where each member is expected to talk to the others. In a large server-system the services might not exist on the same, physical hardware either, so you want to take height for that.
With the SDK this is just another service. It takes 10 minutes to create a DLL server with the functionality to send and receive messages – and then you just load and plug that into all your services. Done. Finished.
Interestingly, Remoting SDK supports named-pipes. So if you are running on a Windows network it’s even easier. Personally I prefer to use a vanilla TCP/IP based server and channel, that way I can make use of my Linux blades too.
Building on the system
There is nothing stopping you from expanding the system that RemObjects have established. You are not forced to only use their server types, message types and class framework. You can mix and match as you see fit – and also inherit out your own variation if you need something special.
For example, WebSocket is an emerging standard that has become wildly popular. Remoting SDK does not support that out of the box, the reason is that the standard is practically identical to the RemObjects super-server, and partly because there must be room for third party vendors.
Andre Mussche took the time to implement a WebSocket server for Remoting SDK a few years back. Demonstrating in the process just how easy it is to build on the existing infrastructure. If you are already using Remoting SDK or want WebSocket support, head over to his github repository and grab the code there: https://github.com/andremussche/DelphiWebsockets
I could probably write a whole book covering this framework. For the past 15 years, RemObjects Remoting SDK is the first product I install after Delphi. It has become standard for me and remains an integral part of my toolkit. Other packages have come and gone, but this one remains.
Hopefully this post has tickled your interest in the product. No matter if you are maintaining a legacy service stack, or thinking about re implementing your existing system in something future-proof, this framework will make your life much, much easier. And it wont break the bank either.
You can visit the product page here: https://www.remotingsdk.com/ro/default.aspx
And you can check out the documentation here: https://docs.remotingsdk.com/
30% discount on all RemObjects products!
This is brilliant. RemObjects is giving a whopping 30% discount on all products!
This means you can now pick up RemObjects Remoting Framework, Data Abstract, Hydra or the Elements compiler toolchain – with a massive 30% saving!
These are battle-hardened, enterprise level solutions that have been polished over years and they are in constant development. Each solution integrates seamlessly into Embarcadero Delphi and provides a smooth path to delivering quality products in days rather than weeks.
But you better hurry because it’s only valid for one week (!)
Use the coupon code: “DelphiDeveloper”
Use the Delphi Developer coupon to get 30% discount – click here
A Delphi propertybag
A long, long time ago, way back in the previous century, I often had to adjust a Visual Basic project my company maintained. Going from object-pascal to VB was more than a little debilitating; Visual Basic was not a compiled language like Delphi is, and it lacked more or less every feature you needed to produce good software.
I could probably make a VB clone using Delphi pretty easily. But I think the world has experienced enough suffering, no need to add more evil to the universe
Having said that, I have always been a huge fan of Basic (it was my first language after all, it’s what schools taught in the 70s and 80s). I think it was a terrible mistake for Microsoft to retire Basic as a language, because it’s a great way to teach kids the fundamentals of programming.
Visual Basic is still there though, available for the .Net framework, but to call it Basic is an insult of the likes of GFA Basic, Amos Basic and Blitz Basic; the mighty compilers of the past. If you enjoyed basic before Microsoft pushed out the monstrosity that is Visual Basic, then perhaps swing by GitHub and pick up a copy of BlitzBasic? BlitzBasic is a completely different beast. It compiles to machine-code, allows inline assembly, and has been wildly popular for game developers over the years.
A property bag
The only feature that I found somewhat useful in Visual Basic, was an object called a propertybag. It’s just a fancy name for a dictionary, but it had a couple of redeeming factors beyond lookup ability. Like being able to load name-value-pairs from a string, recognizing datatypes and exposing type-aware read/write methods. Nothing fancy but handy when dealing with database connection-strings, shell parameters and the like.
So you could feed it strings like this:
first=12;second=hello there;third=3.14
And the class would parse out the names and values, stuff it in a dictionary, and you could easily extract the data you needed. Nothing fancy, but handy on rare occasions.
A Delphi version
Im mostly porting code from Delphi to Oxygene these days, but here is my Delphi implementation of the propertybag object. Please note that I haven’t bothered to implement the propertybag available in .Net. The Delphi version below is based on the Visual Basic 6 version, with some dependency injection thrown in for good measure.
unit fslib.params;
interface
{.$DEFINE SUPPORT_URI_ENCODING}
uses
System.SysUtils,
System.Classes,
Generics.Collections;
type
(* Exceptions *)
EPropertybag = class(exception);
EPropertybagReadError = class(EPropertybag);
EPropertybagWriteError = class(EPropertybag);
EPropertybagParseError = class(EPropertybag);
(* Datatypes *)
TPropertyBagDictionary = TDictionary ;
IPropertyElement = interface
['{C6C937DF-50FA-4984-BA6F-EBB0B367D3F3}']
function GetAsInt: integer;
procedure SetAsInt(const Value: integer);
function GetAsString: string;
procedure SetAsString(const Value: string);
function GetAsBool: boolean;
procedure SetAsBool(const Value: boolean);
function GetAsFloat: double;
procedure SetAsFloat(const Value: double);
function GetEmpty: boolean;
property Empty: boolean read GetEmpty;
property AsFloat: double read GetAsFloat write SetAsFloat;
property AsBoolean: boolean read GetAsBool write SetAsBool;
property AsInteger: integer read GetAsInt write SetAsInt;
property AsString: string read GetAsString write SetAsString;
end;
TPropertyBag = Class(TInterfacedObject)
strict private
FLUT: TPropertyBagDictionary;
strict protected
procedure Parse(NameValuePairs: string);
public
function Read(Name: string): IPropertyElement;
function Write(Name: string; Value: string): IPropertyElement;
procedure SaveToStream(const Stream: TStream);
procedure LoadFromStream(const Stream: TStream);
function ToString: string; override;
procedure Clear; virtual;
constructor Create(NameValuePairs: string); virtual;
destructor Destroy; override;
end;
implementation
{$IFDEF SUPPORT_URI_ENCODING}
uses
system.NetEncoding;
{$ENDIF}
const
cnt_err_sourceparameters_parse =
'Failed to parse input, invalid or damaged text error [%s]';
cnt_err_sourceparameters_write_id =
'Write failed, invalid or empty identifier error';
cnt_err_sourceparameters_read_id =
'Read failed, invalid or empty identifier error';
type
TPropertyElement = class(TInterfacedObject, IPropertyElement)
strict private
FName: string;
FData: string;
FStorage: TPropertyBagDictionary;
strict protected
function GetEmpty: boolean; inline;
function GetAsInt: integer; inline;
procedure SetAsInt(const Value: integer); inline;
function GetAsString: string; inline;
procedure SetAsString(const Value: string); inline;
function GetAsBool: boolean; inline;
procedure SetAsBool(const Value: boolean); inline;
function GetAsFloat: double; inline;
procedure SetAsFloat(const Value: double); inline;
public
property AsFloat: double read GetAsFloat write SetAsFloat;
property AsBoolean: boolean read GetAsBool write SetAsBool;
property AsInteger: integer read GetAsInt write SetAsInt;
property AsString: string read GetAsString write SetAsString;
property Empty: boolean read GetEmpty;
constructor Create(const Storage: TPropertyBagDictionary; Name: string; Data: string); overload; virtual;
constructor Create(Data: string); overload; virtual;
end;
//#############################################################################
// TPropertyElement
//#############################################################################
constructor TPropertyElement.Create(Data: string);
begin
inherited Create;
FData := Data.Trim();
end;
constructor TPropertyElement.Create(const Storage: TPropertyBagDictionary;
Name: string; Data: string);
begin
inherited Create;
FStorage := Storage;
FName := Name.Trim().ToLower();
FData := Data.Trim();
end;
function TPropertyElement.GetEmpty: boolean;
begin
result := FData.Length < 1;
end;
function TPropertyElement.GetAsString: string;
begin
result := FData;
end;
procedure TPropertyElement.SetAsString(const Value: string);
begin
if Value FData then
begin
FData := Value;
if FName.Length > 0 then
begin
if FStorage nil then
FStorage.AddOrSetValue(FName, Value);
end;
end;
end;
function TPropertyElement.GetAsBool: boolean;
begin
TryStrToBool(FData, result);
end;
procedure TPropertyElement.SetAsBool(const Value: boolean);
begin
FData := BoolToStr(Value, true);
if FName.Length > 0 then
begin
if FStorage nil then
FStorage.AddOrSetValue(FName, FData);
end;
end;
function TPropertyElement.GetAsFloat: double;
begin
TryStrToFloat(FData, result);
end;
procedure TPropertyElement.SetAsFloat(const Value: double);
begin
FData := FloatToStr(Value);
if FName.Length > 0 then
begin
if FStorage nil then
FStorage.AddOrSetValue(FName, FData);
end;
end;
function TPropertyElement.GetAsInt: integer;
begin
TryStrToInt(FData, Result);
end;
procedure TPropertyElement.SetAsInt(const Value: integer);
begin
FData := IntToStr(Value);
if FName.Length > 0 then
begin
if FStorage nil then
FStorage.AddOrSetValue(FName, FData);
end;
end;
//#############################################################################
// TPropertyBag
//#############################################################################
constructor TPropertyBag.Create(NameValuePairs: string);
begin
inherited Create;
FLUT := TDictionary.Create();
NameValuePairs := NameValuePairs.Trim();
if NameValuePairs.Length > 0 then
Parse(NameValuePairs);
end;
destructor TPropertyBag.Destroy;
begin
FLut.Free;
inherited;
end;
procedure TPropertyBag.Clear;
begin
FLut.Clear;
end;
procedure TPropertyBag.Parse(NameValuePairs: string);
var
LList: TStringList;
x: integer;
LId: string;
LValue: string;
LOriginal: string;
{$IFDEF SUPPORT_URI_ENCODING}
LPos: integer;
{$ENDIF}
begin
// Reset content
FLUT.Clear();
// Make a copy of the original text
LOriginal := NameValuePairs;
// Trim and prepare
NameValuePairs := NameValuePairs.Trim();
// Anything to work with?
if NameValuePairs.Length > 0 then
begin
{$IFDEF SUPPORT_URI_ENCODING}
// Check if the data is URL-encoded
LPos := pos('%', NameValuePairs);
if (LPos >= low(NameValuePairs) )
and (LPos 0 then
Begin
(* Populate our lookup table *)
LList := TStringList.Create;
try
LList.Delimiter := ';';
LList.StrictDelimiter := true;
LList.DelimitedText := NameValuePairs;
if LList.Count = 0 then
raise EPropertybagParseError.CreateFmt(cnt_err_sourceparameters_parse, [LOriginal]);
try
for x := 0 to LList.Count-1 do
begin
LId := LList.Names[x].Trim().ToLower();
if (LId.Length > 0) then
begin
LValue := LList.ValueFromIndex[x].Trim();
Write(LId, LValue);
end;
end;
except
on e: exception do
raise EPropertybagParseError.CreateFmt(cnt_err_sourceparameters_parse, [LOriginal]);
end;
finally
LList.Free;
end;
end;
end;
end;
function TPropertyBag.ToString: string;
var
LItem: TPair;
begin
setlength(result, 0);
for LItem in FLut do
begin
if LItem.Key.Trim().Length > 0 then
begin
result := result + Format('%s=%s;', [LItem.Key, LItem.Value]);
end;
end;
end;
procedure TPropertyBag.SaveToStream(const Stream: TStream);
var
LData: TStringStream;
begin
LData := TStringStream.Create(ToString(), TEncoding.UTF8);
try
LData.SaveToStream(Stream);
finally
LData.Free;
end;
end;
procedure TPropertyBag.LoadFromStream(const Stream: TStream);
var
LData: TStringStream;
begin
LData := TStringStream.Create('', TEncoding.UTF8);
try
LData.LoadFromStream(Stream);
Parse(LData.DataString);
finally
LData.Free;
end;
end;
function TPropertyBag.Write(Name: string; Value: string): IPropertyElement;
begin
Name := Name.Trim().ToLower();
if Name.Length > 0 then
begin
if not FLUT.ContainsKey(Name) then
FLut.Add(Name, Value);
result := TPropertyElement.Create(FLut, Name, Value) as IPropertyElement;
end else
raise EPropertybagWriteError.Create(cnt_err_sourceparameters_write_id);
end;
function TPropertyBag.Read(Name: string): IPropertyElement;
var
LData: String;
begin
Name := Name.Trim().ToLower();
if Name.Length > 0 then
begin
if FLut.TryGetValue(Name, LData) then
result := TPropertyElement.Create(LData) as IPropertyElement
else
raise EPropertybagReadError.Create(cnt_err_sourceparameters_read_id);
end else
raise EPropertybagReadError.Create(cnt_err_sourceparameters_read_id);
end;
end.
BTree for Delphi
Click here to read
A few weeks back I posted an article on RemObjects blog regarding universal code, and how you with a little bit of care can write code that easily compiled with both Oxygene, Delphi and Freepascal. With emphasis on Oxygene.
The example I used was a BTree class that I originally ported from Delphi to Smart Pascal, and then finally to Oxygene to run under WebAssembly.
Long story short I was asked if I could port the code back to Delphi in its more or less universal form. Naturally there are small differences here and there, but nothing special that distinctly separates the Delphi version from Oxygene or Smart Pascal.
Why this version?
If you google BTree and Delphi you will find loads of implementations. They all operate more or less identical, using records and pointers for optimal speed. I decided to base my version on classes for convenience, but it shouldn’t be difficult to revert that to use records if you absolutely need it.
What I like about this BTree implementation is that it’s very functional. Its easy to traverse the nodes using the ForEach() method, you can add items using a number as an identifier, but it also supports string identifiers.
I also changed the typical data reference. The data each node represent is usually a pointer. I changed this to variant to make it more functional.
Well, here is the Delphi version as promised. Happy to help.
unit btree;
interface
uses
System.Generics.Collections,
System.Sysutils,
System.Classes;
type
// BTree leaf object
TQTXBTreeNode = class(TObject)
public
Identifier: integer;
Data: variant;
Left: TQTXBTreeNode;
Right: TQTXBTreeNode;
end;
[Weak]
TQTXBTreeProcessCB = reference to procedure (const Node: TQTXBTreeNode; var Cancel: boolean);
EBTreeError = class(Exception);
TQTXBTree = class(TObject)
private
FRoot: TQTXBTreeNode;
FCurrent: TQTXBTreeNode;
protected
function GetEmpty: boolean; virtual;
function GetPackedNodes: TList;
public
property Root: TQTXBTreeNode read FRoot;
property Empty: boolean read GetEmpty;
function Add(const Ident: integer; const Data: variant): TQTXBTreeNode; overload; virtual;
function Add(const Ident: string; const Data: variant): TQTXBTreeNode; overload; virtual;
function Contains(const Ident: integer): boolean; overload; virtual;
function Contains(const Ident: string): boolean; overload; virtual;
function Remove(const Ident: integer): boolean; overload; virtual;
function Remove(const Ident: string): boolean; overload; virtual;
function Read(const Ident: integer): variant; overload; virtual;
function Read(const Ident: string): variant; overload; virtual;
procedure Write(const Ident: string; const NewData: variant); overload; virtual;
procedure Write(const Ident: integer; const NewData: variant); overload; virtual;
procedure Clear; overload; virtual;
procedure Clear(const Process: TQTXBTreeProcessCB); overload; virtual;
function ToDataArray: TList;
function Count: integer;
procedure ForEach(const Process: TQTXBTreeProcessCB);
destructor Destroy; override;
end;
implementation
//#############################################################################
// TQTXBTree
//#############################################################################
destructor TQTXBTree.Destroy;
begin
if FRoot nil then
Clear();
inherited;
end;
procedure TQTXBTree.Clear;
var
lTemp: TList;
x: integer;
begin
if FRoot nil then
begin
// pack all nodes to a linear list
lTemp := GetPackedNodes();
try
// release each node
for x := 0 to ltemp.Count-1 do
begin
lTemp[x].Free;
end;
finally
// dispose of list
lTemp.Free;
// reset pointers
FCurrent := nil;
FRoot := nil;
end;
end;
end;
procedure TQTXBTree.Clear(const Process: TQTXBTreeProcessCB);
begin
ForEach(Process);
Clear();
end;
function TQTXBTree.GetPackedNodes: TList;
var
LData: Tlist;
begin
LData := TList.Create();
ForEach( procedure (const Node: TQTXBTreeNode; var Cancel: boolean)
begin
LData.Add(Node);
Cancel := false;
end);
result := LData;
end;
function TQTXBTree.GetEmpty: boolean;
begin
result := FRoot = nil;
end;
function TQTXBTree.Count: integer;
var
LCount: integer;
begin
ForEach( procedure (const Node: TQTXBTreeNode; var Cancel: boolean)
begin
inc(LCount);
Cancel := false;
end);
result := LCount;
end;
function TQTXBTree.ToDataArray: TList;
var
Data: TList;
begin
Data := TList.Create();
ForEach( procedure (const Node: TQTXBTreeNode; var Cancel: boolean)
begin
Data.add(Node.data);
Cancel := false;
end);
result := data;
end;
function TQTXBTree.Add(const Ident: string; const Data: variant): TQTXBTreeNode;
begin
result := Add( Ident.GetHashCode(), Data);
end;
function TQTXBTree.Add(const Ident: integer; const Data: variant): TQTXBTreeNode;
var
lNode: TQTXBtreeNode;
begin
LNode := TQTXBTreeNode.Create();
LNode.Identifier := Ident;
LNode.Data := data;
if FRoot = nil then
FRoot := LNode;
FCurrent := FRoot;
while true do
begin
if (Ident FCurrent.Identifier) then
begin
if (FCurrent.right = nil) then
begin
FCurrent.right := LNode;
break;
end else
FCurrent := FCurrent.right;
end else
break;
end;
result := LNode;
end;
function TQTXBTree.Read(const Ident: string): variant;
begin
result := Read( Ident.GetHashCode() );
end;
function TQTXBTree.Read(const Ident: integer): variant;
begin
FCurrent := FRoot;
while FCurrent nil do
begin
if (Ident Fcurrent.Identifier) then
FCurrent := FCurrent.Right
else
begin
result := FCUrrent.Data;
break;
end
end;
end;
procedure TQTXBTree.Write(const Ident: string; const NewData: variant);
begin
Write( Ident.GetHashCode(), NewData);
end;
procedure TQTXBTree.Write(const Ident: integer; const NewData: variant);
begin
FCurrent := FRoot;
while (FCurrent nil) do
begin
if (Ident Fcurrent.Identifier) then
FCurrent := FCurrent.Right
else
begin
FCurrent.Data := NewData;
break;
end
end;
end;
function TQTXBTree.Contains(const Ident: string): boolean;
begin
result := Contains( Ident.GetHashCode() );
end;
function TQTXBTree.Contains(const Ident: integer): boolean;
begin
result := false;
if FRoot nil then
begin
FCurrent := FRoot;
while ( (not Result) and (FCurrent nil) ) do
begin
if (Ident Fcurrent.Identifier) then
FCurrent := FCurrent.Right
else
begin
Result := true;
break;
end
end;
end;
end;
function TQTXBTree.Remove(const Ident: string): boolean;
begin
result := Remove( Ident.GetHashCode() );
end;
function TQTXBTree.Remove(const Ident: integer): boolean;
var
LFound: boolean;
LParent: TQTXBTreeNode;
LReplacement,
LReplacementParent: TQTXBTreeNode;
LChildCount: integer;
begin
FCurrent := FRoot;
LFound := false;
LParent := nil;
LReplacement := nil;
LReplacementParent := nil;
while (not LFound) and (FCurrent nil) do
begin
if (Ident FCurrent.Identifier) then
begin
LParent := FCurrent;
FCurrent := FCurrent.right;
end else
LFound := true;
if LFound then
begin
LChildCount := 0;
if (FCurrent.left nil) then
inc(LChildCount);
if (FCurrent.right nil) then
inc(LChildCount);
if FCurrent = FRoot then
begin
case (LChildCOunt) of
0: begin
FRoot := nil;
end;
1: begin
if FCurrent.right = nil then
FRoot := FCurrent.left
else
FRoot :=FCurrent.Right;
end;
2: begin
LReplacement := FRoot.left;
while (LReplacement.right nil) do
begin
LReplacementParent := LReplacement;
LReplacement := LReplacement.right;
end;
if (LReplacementParent nil) then
begin
LReplacementParent.right := LReplacement.Left;
LReplacement.right := FRoot.Right;
LReplacement.left := FRoot.left;
end else
LReplacement.right := FRoot.right;
end;
end;
FRoot := LReplacement;
end else
begin
case LChildCount of
0: if (FCurrent.Identifier < LParent.Identifier) then
Lparent.left := nil else
LParent.right := nil;
1: if (FCurrent.Identifier < LParent.Identifier) then
begin
if (FCurrent.Left = NIL) then
LParent.left := FCurrent.Right else
LParent.Left := FCurrent.Left;
end else
begin
if (FCurrent.Left = NIL) then
LParent.right := FCurrent.Right else
LParent.right := FCurrent.Left;
end;
2: begin
LReplacement := FCurrent.left;
LReplacementParent := FCurrent;
while LReplacement.right nil do
begin
LReplacementParent := LReplacement;
LReplacement := LReplacement.right;
end;
LReplacementParent.right := LReplacement.left;
LReplacement.right := FCurrent.right;
LReplacement.left := FCurrent.left;
if (FCurrent.Identifier < LParent.Identifier) then
LParent.left := LReplacement
else
LParent.right := LReplacement;
end;
end;
end;
end;
end;
result := LFound;
end;
procedure TQTXBTree.ForEach(const Process: TQTXBTreeProcessCB);
function ProcessNode(const Node: TQTXBTreeNode): boolean;
begin
if Node nil then
begin
if Node.left nil then
begin
result := ProcessNode(Node.left);
if result then
exit;
end;
Process(Node, result);
if result then
exit;
if (Node.right nil) then
begin
result := ProcessNode(Node.right);
if result then
exit;
end;
end;
end;
begin
ProcessNode(FRoot);
end;
end.
Calling node.js from Delphi
We got a good question about how to start a node.js program from Delphi on our Facebook group today (third one in a week?). When you have been coding for years you often forget that things like this might not be immediately obvious. Hopefully I can shed some light on the options in this post.
Node or chrome?
Just to be clear: node.js has nothing to do with chrome or chromium embedded. Chrome is a web-browser, a completely visual environment and ecosystem.
Node.js is the complete opposite. It is purely a shell based environment, meaning that it’s designed to run services and servers, with emphasis on the latter.
The only thing node.js and chrome have in common, is that they both use the V8 JavaScript runtime engine to load, JIT compile and execute scripts at high speed. Beyond that, they are utterly alien to each other.
Can node.js be embedded into a Delphi program?
Technically there is nothing stopping a C/C++ developer from compiling the node.js core system as C++ builder compatible .obj files; files that can then be linked into a Delphi application through references. But this also requires a bit of scaffolding, like adding support for malloc_, free_ and a few other procedures – so that your .obj files uses the same memory manager as your Delphi code. But until someone does just that and publish it, im afraid you are stuck with two options:
- Use a library called Toby, that keeps node.js in a single DLL file. This is the most practical way if you insist on hosting your own version of node.js
- Add node.js as a prerequisite and give users the option to locate the node.exe in your application’s preferences. This is the way I would go, because you really don’t want to force users to stick with your potentially outdated or buggy build.
So yes, you can use toby and just add the toby dll file to your program folder, but I have to strongly advice against that. There is no point setting yourself up for maintaining a whole separate programming language, just because you want JavaScript support.
“How many in your company can write high quality WebAssembly modules?”
If all you want to do is support JavaScript in your application, then I would much rather install Besen into Delphi. Besen is a JavaScript runtime engine written in Freepascal. It is fully compatible with Delphi, and follows the ECMA standard to the letter. So it is extremely compatible, fast and easy to use.
Like all Delphi components Besen is compiled into your application, so you have no dependencies to worry about.
Starting a node.js script
The easiest way to start a node.js script, is to simply shell-execute out of your Delphi application. This can be done as easily as:
ShellExecute(Handle, 'open', PChar('node.exe'), pchar('script.js'), nil, SW_SHOW);
This is more than enough if you just want to start a service, server or do some work that doesn’t require that you capture the result.
If you need to capture the result, the data that your node.js program emits on stdout, there is a nice component in the Jedi Component Library. Also plenty of examples online on how to do that.
If you need even further communication, you need to look for a shell-execute that support pipes. All node.js programs have something called a message-channel in the Javascript world. In reality though, this is just a named pipe that is automatically created when your script starts (with the same moniker as the PID [process identifier]).
If you opt for the latter you have a direct, full duplex message channel directly into your node.js application. You just have to agree with yourself on a protocol so that your Delphi code understands what node.js is saying, and visa versa.
UDP or TCP
If you don’t want to get your hands dirty with named pipes and rolling your own protocol, you can just use UDP to let your Delphi application communicate with your node.js process. UDP is practically without cost since its fundamental to all networking stacks, and in your case you will be shipping messages purely between processes on localhost. Meaning: packets are never sent on the network, but rather delegated between processes on the same machine.
In that case, I suggest you ship in the port you want your UDP server to listen on, so that your node.js service acts as the server. A simple command-line statement like:
node.exe myservice.js 8090
Inside node.js you can setup an UDP server with very little fuzz:
function setupServer(port) {
var os = require("os");
var dgram = require("dgram");
var socket = dgram.createSocket("udp4");
var MULTICAST_HOST = "224.0.0.236";
var BROADCAST_HOST = "255.255.255.255";
var ALL_PORT = 60540;
var MULTICAST_TTL = 1; // Local network
socket.bind(port);
socket.on('listening', function() {
socket.setMulticastLoopback(true);
socket.setMulticastTTL(MULTICAST_TTL);
socket.addMembership(multicastHost);
if(broadcast) { socket.setBroadcast(true); }
});
socket.on('message', parseMessage);
}
function parseMessage(message, rinfo) {
try {
var messageObject = JSON.parse(message);
var eventType = messageObject.eventType;
} catch(e) {
}
}
Note: the code above assumes a JSON text message.
You can then use any Delphi UDP client to communicate with your node.js server, Indy is good, Synapse is a good library with less overhead – there are many options here.
Do I have to learn Javascript to use node.js?
If you download DWScript you can hook-up the JS-codegen library (see library folder in the DWScript repository), and use that to compile DWScript (object pascal) to kick-ass Javascript. This is the same compiler that was used in Smart Mobile Studio.
“Adding WebAssembly to your resume is going to be a hell of a lot more valuable in the years to come than C# or Java”
Another alternative is to use Freepascal, they have a pas2js project where you can compile ordinary object-pascal to javascript. Naturally there are a few things to keep in mind, both for DWScript and Freepascal – like avoiding pointers. But clean object pascal compiles just fine.
If JavaScript is not your cup of tea, or you simply don’t have time to learn the delicate nuances between the DOM (document object model, used by browsers) and the 100% package oriented approach deployed by node.js — then you can just straight up to webassembly.
RemObjects Software has a kick-ass webassembly compiler, perfect if you dont have the energy or time to learn JavaScript. As of writing this is the fastest and most powerful toolchain available. And I have tested them all.
WebAssembly, no Javascript needed
You might remember Oxygene? It used to be shipped with Delphi as a way to target Microsoft CLR (common language runtime) and the .net framework.
Since then Oxygene and the RemObjects toolchain has evolved dramatically and is now capable of a lot more than CLR support.
- You can compile to raw, llvm optimized machine code for 8 platforms
- You can compile to CLR/.Net
- You can compile to Java bytecodes
- You can compile to WebAssembly!
WebAssembly is not Javascript, it’s important to underline that. WebAssembly was created especially for developers using traditional languages, so that traditional compilers can emit web friendly, binary code. Unlike Javascript, WebAssembly is a purely binary format. Just like Delphi generates machine-code that is linked into a final executable, WebAssembly is likewise compiled, linked and emitted in binary form.
If that sounds like a sales pitch, it’s not. It’s a matter of practicality.
- WebAssembly is completely barren out of the box. The runtime environment, be it V8 for the browser or V8 for node.js, gives you nothing out of the box. You don’t even have WriteLn() to emit text.
- Google expects compiler makers to provide their own RTL functions, from the fundamental to the advanced. The only thing V8 gives you, is a barebone way of referencing objects and functions on the other side, meaning the JS and DOM world. And that’s it.
So the reason i’m talking a lot about Oxygene and RemObjects Elements (Elements is the name of the compiler toolchain RemObjects offers), is because it ships with an RTL. So you are not forced to start on actual, literal assembly level.
If you don’t want to study JavaScript, Oxygene and Elements from RemObjects is the solution
RemObjects also delivers a DelphiVCL compatibility framework. This is a clone of the Delphi VCL / Freepascal LCL. Since WebAssembly is still brand new, work is being done on this framework on a daily basis, with updates being issued all the time.
Note: The Delphi VCL framework is not just for WebAssembly. It represents a unified framework that can work anywhere. So if you switch from WebAssembly to say Android, you get the same result.
The most important part of the above, is actually not the visual stuff. I mean, having HTML5 visual controls is cool – but chances are you want to use a library like Sencha, SwiftUI or jQueryUI to compose your forms right? Which means you just want to interface with the widgets in the DOM to set and get values.
You probably want to use a fancy UI library, like jQuery UI. This works perfectly with Elements because you can reference the controls from your WebAssembly module. You dont have to create TButton, TListbox etc manually
The more interesting stuff is actually the non-visual code you get access to. Hundreds of familiar classes from the VCL, painstakingly re-created, and usable from any of the 5 languages Elements supports.
You can check it out here: https://github.com/remobjects/DelphiRTL
Skipping JavaScript all together
I dont believe in single languages. Not any more. There was a time when all you needed was Delphi and a diploma and you were set to conquer the world. But those days are long gone, and a programmer needs to be flexible and have a well stocked toolbox.
Knowing where you want to be is half the journey
The world really don’t need yet-another-c# developer. There are millions of C# developers in India alone. C# is just “so what?”. Which is also why C# jobs pays less than Delphi or node.js system service jobs.
What you want, is to learn the things others avoid. If JavaScript looks alien and you feel uneasy about the whole thing – that means you are growing as a developer. All new things are learned by venturing outside your comfort zone.
How many in your company can write high quality WebAssembly modules?
How many within one hour driving distance from your office or home are experts at WebAssembly? How many are capable of writing industrial scale, production ready system services for node.js that can scale from a single instance to 1000 instances in a large, clustered cloud environment?
Any idiot can pick up node.js and knock out a service, but with your background from Delphi or C++ builder you have a massive advantage. All those places that can throw an exception that JS devs usually ignore? As a Delphi or Oxygene developer you know better. And when you re-apply that experience under a different language, suddenly you can do stuff others cant. Which makes your skills valuable.
The Quartex Media Desktop have made even experienced node / web developers gasp. They are not used to writing custom-controls and large-scale systems, which is my advantage
So would you learn JavaScript or just skip to WebAssembly? Honestly? Learn a bit of both. You don’t have to be an expert in JavaScript to compliment WebAssembly. Just get a cheap book, like “Node.js for beginners” and “JavaScript the good parts” ($20 a piece) and that should be more than enough to cover the JS side of things.
Adding WebAssembly to your resume and having the material to prove you know your stuff, is going to be a hell of a lot more valuable in the years to come than C#, Java or Python. THAT I can guarantee you.
And, we have a wicked cool group on Facebook you can join too: Click here to visit RemObjects Developer.
Getting into Node.js from Delphi
Delphi is one of the best development toolchains for Windows. I have been an avid fan of Delphi since it was first released, and before that – Turbo Pascal too. Delphi has a healthy following – and despite popular belief, Delphi scores quite well on the Tiobe Index.
As cool and efficient as Delphi might be, there are situations where native code wont work. Or at the very least, be less efficient than the alternatives. Delphi has a broad wingspan, from low-level assembler all the way to classes and generics. But JavaScript and emerging web technology is based on a completely different philosophy, one where native code is regarded as negative since it binds you to hardware.
Getting to grips with the whole JavaScript phenomenon, be it for mobile, embedded or back-end services, can be daunting if all you know is native code. But thankfully there are alternatives that can help you become productive quickly, something I will brush over in this post.
JavaScript without JavaScript
Before we dig into the tools of the trade, I want to cover alternative ways of enjoying the power of node.js and Javascript. Namely by using compilers that can convert code from a traditional language – and emit fully working JavaScript. There are a lot more options than you think:
Quartex Media Desktop is a complete environment written purely in JavaScript. Both Server, Cluster and front-end is pure JavaScript. A good example of what can be done.
- Swift compiles for JavaScript, and Apple is doing some amazing things with the new and sexy SwiftUI tookit. If you know your way around Swift, you can compile for Javascript
- Go can likewise be compiled to JS:
- C/C++ can be compiled to asm.js courtesy of EmScripten. It uses clang to first compile your code to llvm bitcode, and then it converts that into asm.js. You have probably seen games like Quake run in the browser? That was asm.js, a kind of precursor to WebAssembly.
- NS Basic compiles for JavaScript, this is a Visual Basic 6 style environment with its own IDE even
For those coming straight from Delphi, there are a couple of options to pick from:
- Freepascal (pas2js project)
- DWScript compiles code to JavaScript, this is the same compiler that we used in Smart Pascal earlier
- Oxygene, the next generation object-pascal from RemObjects compiles to WebAssembly. This is by far the best option of them all.
I strongly urge you to have a look at Elements, here running in Visual Studio
JavaScript, Asm.js or WebAssembly?
Asm.js is by far the most misunderstood technology in the JavaScript ecosystem, so let me just cover that before we move on:
A few years back JavaScript gained support for memory buffers and typed arrays. This might not sound very exciting, but in terms of speed – the difference is tremendous. The default variable type in JavaScript is what Delphi developers know as Variant. It assumes the datatype of the values you assign to it. Needless to say, there is a lot of overhead when working with variants – so JavaScript suddenly getting proper typed arrays was a huge deal.
It was then discovered that JavaScript could manipulate these arrays and buffers at high speed, providing it only used a subset of the language. A subset that the JavaScript runtime could JIT compile more easily (turn into machine-code).
So what the EmScripten team did was to implement a bytecode based virtual-machine in Javascript, and then they compile C/C++ to bytecodes. I know, it’s a huge project, but the results speak for themselves — before WebAssembly, this was as fast as it got with JavaScript.
WebAssembly
WebAssembly is different from both vanilla JavaScript and Asm.js. First of all, it’s executed at high speed by the browser itself. Not like asm.js where these bytecodes were executed by JavaScript code.
Water is a fast, slick and platform independent IDE for Elements. The same IDE for OS X is called Fire. You can use RemObjects Elements from either Visual Studio or Water
Secondly, WebAssembly is completely JIT compiled by the browser or node.js when loading. It’s not like Asm.js where some parts are compiled, others are interpreted. WebAssembly runs at full speed and have nothing to do with traditional JavaScript. It’s actually a completely separate engine.
Out of all the options on the table, WebAssembly is the technology with the best performance.
Kits and strategies
The first thing you need to be clear about, is what you want to work with. The needs and requirements of a game developer will be very different from a system service developer.
Here are a couple of kits to think about:
- Mobile developer
- Implement your mobile applications using Oxygene, compiling for WebAssembly (Elements)
- RemObjects Remoting SDK for client / server communication
- Use Freepascal for vanilla JavaScript scaffolding when needed
- Service developer
- Implement libraries in Oxygene to benefit from the speed of WebAssembly
- Use RemObjects Data Abstract to make data-access uniform and fast
- Use Freepascal for boilerplate node.js logic
- Desktop developer
- For platform independent desktop applications, WebAssembly is the way to go. You will need some scaffolding (plain Javascript) to communicate with the application host – but the 99.9% of your code will be better under WebAssembly.
- Use Cordova / Phonegap to “bundle” your WebAssembly, HTML5 files and CSS styling into a single, final executable.
The most important part to think about when getting into JavaScript, is to look closely at the benefits and limitation of each technology.
WebAssembly is fast, wicked fast, and let’s you write code like you are used to from Delphi. Things like pointers etc are supported in Elements, which means ordinary code that use pointers will port over with ease. You are also not bound on hand-and-feet to a particular framework.
For example, EmScripten for C/C++ have almost nothing in terms of UI functionality. The visual part is a custom build of SDL (simple directmedia layer), which fakes the graphics onto an ordinary HTML5 canvas. This makes EmScripten a good candidate for porting games written in C/C++ to the web — but it’s less than optimal for writing serious applications.
Setting up the common tools
So far we have looked at a couple of alternatives for getting into the wonderful world of JavaScript in lieu of other languages. But what if you just want to get started with the typical tools JS developers use?
Visual Studio Code is a pretty amazing code-editor
The first “must have” is Visual Studio Code. This is actually a great example of what you can achieve with JavaScript, because the entire editor and program is written in JavaScript. But I want to stress that this editor is THE editor to get. The way you work with files in JS is very different from Delphi, C# and Java. JavaScript projects are often more fragmented, with less code in each file – organized by name.
TypeScript was invented by Anders Hejlsberg, who also made Delphi and C#
The next “must have” is without a doubt TypeScript. Personally im not too fond of TypeScript, but if ordinary JavaScript makes your head hurt and you want classes and ordinary inheritance, then TypeScript is a step up.
Next on the list is AssemblyScript. This is a post-processor for TypeScript that converts your code into WebAssembly. It lacks much of the charm and elegance of Oxygene, but I suspect that has to do with old habits. When you have been reading object-pascal for 20 years, you feel more at home there.
You will also need to install node.js, which is the runtime engine for running JavaScript as services. Node.js is heavily optimized for writing server software, but it’s actually a brilliant way to write services that are multi-platform. Because Node.js delivers the same behavior regardless of underlying operating system.
And finally, since you definitely want to convert your JavaScript and/or WebAssembly into a stand-alone executable: you will need Adobe Phonegap.
Visual Studio
No matter if you want to enter JavaScript via Elements or something else, Visual Studio will save you a lot of time, especially if you plan on targeting Azure or Amazon services. Downloading and installing the community edition is a good idea, and you can use that while exploring your options.
When it comes to writing system services, you also want to check out NPM, the node.js package manager. The JavaScript ecosystem is heavily package oriented – and npm gives you some 800.000 packages to play with free of charge.
Just to be clear, npm is a shell command you use to install or remove packages. NPM is also a online repository of said packages, where you can search and find what you need. Most packages are hosted on github, but when you install a package locally into your application folder – npm figures out dependencies etc. automatically for you.
Books, glorious books
Last but not least, get some good books. Seriously, it will save you so much time and frustration. Amazon have tons of great books, be it vanilla JavaScript, TypeScript, Node.js — pick some good ones and take the time to consume the material.
And again, I strongly urge you to have a look at Elements when it comes to WebAssembly. WebAssembly is a harsh and barren canvas, and being able to use the Elements RTL is a huge boost.
But regardless of path you pick, you will always benefit from learning vanilla JavaScript.
Two new groups in the Developer family
Delphi Developer is a group on Facebook that have been going strong for 12+ years. It was one of the first groups on Facebook, created the same week that Facebook allowed groups. With that group well established, it’s time to expand and clean up the feed.
Last month I introduced a new group, RemObjects Developer, which is a group for developers that use RemObjects components, like the Remoting SDK, Data Abstract and/or Hydra – but more in particular, developers using Oxygene, C#, Swift, Java or Go via Elements (RemObjects compiler toolchain).
Two new groups
To further simplify syndication, and clean up the feeds (which so far has been a pot-purrey of many topics, dialects and products) an additional two groups is now in place:
Obviously there will be some overlapping. Since FPC and Delphi has much in common and are for the most part compatible, some news will be shared between those groups. But all in all this is to clean up the newsfeed which has so far been a mix and match of everything.
Simple overview of the groups
Node.js Developer is not meant to be purely about vanilla JavaScript. Node.js is ultimately a JavaScript runtime-engine. Which means you can use it to run or host WebAssembly libraries (as produced by Oxygene), or generate code via DWScript or Freepascal. You can think of it as a service-host if you like.
So if you are writing WebAssembly applications using Elements, then the node.js group will no doubt be interesting too. Same goes for DWScript users, Smart Pascal users and Freepascal users – providing web tech is what they like.
What is this Quartex Components?
It’s easier to manage multiple groups if you attach them to a parent-page. So if you wonder why all the groups says “by Quartex Components”, that is just a top-level page that helps me deal with with syndication. For some reason Facebook’s API only works for pages, not groups. So it’s impossible to auto-import news (for example) without a page.
The name, “Quartex Components” is ultimately the name of my personal company. I used to produce security components for Delphi, but decided to open-source those for the community.
So Quartex Components is just an organizational element.
Porting TextCraft to Oxygene
TextCraft is a simple yet powerful text parser, designed for general purpose parsing jobs. I originally implemented it for Delphi, it’s the base-parser for the LDEF bytecode assembler amongst other things. It was ported to Smart Pascal, then Freepascal – and now finally Oxygene.
The LDEF Assembler is a part of the Quartex Media Desktop
The LDEF assembler and bytecode engine is currently implemented in Smart and compiles for Javascript. It’s a complete assembler and VM allowing coders to approach Asm.js from an established instruction-set. In short: you feed it source-code, it spits out bytecodes that you can execute super fast in either the browser or elsewhere. As long as there is a VM implementation available.
The Javascript version works really well, especially on node.js. In essence, i don’t need to re-compile the toolchain when moving between arm, x86, windows, linux or osx. Think of it as a type of Java bytecodes or CLR bytecodes.
Getting the code to run under Oxygene, means that I can move the whole engine into WebAssembly. The parser, assembler and linker (et-al) can thus run as WebAssembly, and I can use that from my JavaScript front-end code. Best of both worlds – the flamboyant creativity of JavaScript, and the raw speed of WebAssembly.
The port
Before I can move over the top-level parser + assembler etc, the generic parser code has to work. I was reluctant to start because I imagined the porting would take at least a day, but luckily it took me less than an hour. There are a few superficial differences between Smart, Delphi, Freepascal and Oxygene; for example the Copy() function for strings is not a lose function in Oxygene, instead you use String.SubString(). Functions like High() and Low() on strings likewise has to be refactored.
But all in all the conversion was straight-forward, and TextCraft is now a part of the QTX library for Oxygene. I’ll be uploading a commit to GIT with the whole shabam soon.
Well, hope the WordPress parser doesnt screw this up too bad.
namespace qtxlib;
//##################################################################
// TextCraft 1.2
// Written by Jon L. Aasenden
//
// This is a port of TC 1.2 from Freepascal. TextCraft is initially
// a Delphi parser framework. The original repository can be found
// on BitBucket at:
//
// https://bitbucket.org/hexmonks/main
//
//##################################################################
{$DEFINE USE_INCLUSIVE}
{$define USE_BMARK}
interface
uses
qtxlib, System, rtl,
RemObjects.Elements.RTL.Delphi,
RemObjects.Elements.RTL.Delphi.VCL;
type
// forward declarations
TTextBuffer = class;
TParserContext = class;
TCustomParser = class;
TParserModelObject = class;
// Exceptions
ETextBuffer = class(Exception);
EModelObject = class(Exception);
// Callback functions
TTextValidCB = function (Item: Char): Boolean;
// Bookmark datatype
TTextBufferBookmark = class
public
property bbOffset: Integer;
property bbCol: Integer;
property bbRow: Integer;
function Equals(const ThisMark: TTextBufferBookmark): Boolean;
end;
{.$DEFINE USE_BMARK}
TTextBuffer = class(TErrorObject)
private
FData: String;
FOffset: Integer;
FLength: Integer;
FCol: Integer;
FRow: Integer;
{$IFDEF USE_BMARK}
FBookmarks: List;
{$ENDIF}
procedure SetCacheData(NewText: String);
public
property Column: Integer read FCol;
property Row: Integer read FRow;
property Count: Integer read FLength;
property Offset: Integer read FOffset;
property CacheData: String read FData write SetCacheData;
// These functions map directly to the "Current"
// character where the offset is placed, and is used to
// write code that makes more sense to human eyes
function CrLf: Boolean;
function Space: Boolean;
function Tab: Boolean;
function SemiColon: Boolean;
function Colon: Boolean;
function ConditionEnter: Boolean;
function ConditionLeave: Boolean;
function BracketEnter: Boolean;
function BracketLeave: Boolean;
function Ptr: Boolean;
function Punctum: Boolean;
function Question: Boolean;
function Less: Boolean;
function More: Boolean;
function Equal: Boolean;
function Pipe: Boolean;
function Numeric: Boolean;
function Empty: Boolean;
function BOF: Boolean;
function EOF: Boolean;
function Current: Char;
function First: Boolean;
function Last: Boolean;
// Same as "Next", but does not automatically
// consume CR+LF, used when parsing textfragments
function NextNoCrLf: Boolean;
// Normal Next function, will automatically consume
// CRLF when it encounters it
function Next: Boolean;
function Back: Boolean;
function Bookmark: TTextBufferBookmark;
procedure Restore(const Mark: TTextBufferBookmark);
{$IFDEF USE_BMARK}
procedure Drop;
{$ENDIF}
procedure ConsumeJunk;
procedure ConsumeCRLF;
function Compare(const CompareText: String;
const CaseSensitive: Boolean): Boolean;
function Read(var Fragment: Char): Boolean; overload;
function Read: Char; overload;
function ReadTo(const CB: TTextValidCB; var TextRead: String): Boolean; overload;
function ReadTo(const Resignators: TSysCharSet; var TextRead: String): Boolean; overload;
function ReadTo(MatchText: String): Boolean; overload;
function ReadTo(MatchText: String; var TextRead: String): Boolean; overload;
function ReadToEOL: Boolean; overload;
function ReadToEOL(var TextRead: String): Boolean; overload;
function Peek: Char; overload;
function Peek(CharCount: Integer; var TextRead: String): Boolean; overload;
function NextNonControlChar(const CompareWith: Char): Boolean;
function NextNonControlText(const CompareWith: String): Boolean;
function ReadWord(var TextRead: String): Boolean;
function ReadQuotedString: String;
function ReadCommaList(var cList: List): Boolean;
function NextLine: Boolean;
procedure Inject(const TextToInject: String);
function GetCurrentLocation: TTextBufferBookmark;
function Trail: String;
procedure Clear;
procedure LoadBufferText(const NewBuffer: String);
constructor Create(const BufferText: String); overload; virtual;
finalizer;
begin
{$IFDEF USE_BMARK}
FBookmarks.Clear();
disposeAndNil(FBookmarks);
{$endif}
Clear();
end;
end;
TParserContext = class(TErrorObject)
private
FBuffer: TTextBuffer;
FStack: Stack;
public
property Buffer: TTextBuffer read FBuffer;
property Model: TParserModelObject;
procedure Push(const ModelObj: TParserModelObject);
function Pop: TParserModelObject;
function Peek: TParserModelObject;
procedure ClearStack;
constructor Create(const SourceCode: String); reintroduce; virtual;
finalizer;
begin
FStack.Clear();
FBuffer.Clear();
disposeAndNil(FStack);
disposeAndNil(FBuffer);
end;
end;
TCustomParser = class(TErrorObject)
private
FContext: TParserContext;
protected
procedure SetContext(const NewContext: TParserContext);
public
property Context: TParserContext read FContext;
function Parse: Boolean; virtual;
constructor Create(const ParseContext: TParserContext); reintroduce; virtual;
end;
TParserModelObject = class(TObject)
private
FParent: TParserModelObject;
FChildren: List;
protected
function GetParent: TParserModelObject; virtual;
function ChildGetCount: Integer; virtual;
function ChildGetItem(const Index: Integer): TParserModelObject; virtual;
function ChildAdd(const Instance: TParserModelObject): TParserModelObject; virtual;
public
property Parent: TParserModelObject read GetParent;
property Context: TParserContext;
procedure Clear; virtual;
constructor Create(const AParent: TParserModelObject); virtual;
finalizer;
begin
Clear();
FChildren := nil;
end;
end;
implementation
//#####################################################################
// Error messages
//#####################################################################
const
CNT_ERR_BUFFER_EMPTY = 'Buffer is empty error';
CNT_ERR_OFFSET_BOF = 'Offset at BOF error';
CNT_ERR_OFFSET_EOF = 'Offset at EOF error';
CNT_ERR_COMMENT_NOTCLOSED = 'Comment not closed error';
CNT_ERR_OFFSET_EXPECTED_EOF = 'Expected EOF error';
CNT_ERR_LENGTH_INVALID = 'Invalid length error';
//#####################################################################
// TTextBufferBookmark
//#####################################################################
function TTextBufferBookmark.Equals(const ThisMark: TTextBufferBookmark): boolean;
begin
result := ( (ThisMark nil) and (ThisMark self) )
and (self.bbOffset = ThisMark.bbOffset)
and (self.bbCol = ThisMark.bbCol)
and (self.bbRow = ThisMark.bbRow);
end;
//#####################################################################
// TTextBuffer
//#####################################################################
constructor TTextBuffer.Create(const BufferText: string);
begin
inherited Create();
if length(BufferText) > 0 then
LoadBufferText(BufferText)
else
Clear();
end;
procedure TTextBuffer.Clear;
begin
FData := '';
FOffset := -1;
FLength := 0;
FCol := -1;
FRow := -1;
{$IFDEF USE_BMARK}
FBookmarks.Clear();
{$ENDIF}
end;
procedure TTextBuffer.SetCacheData(NewText: string);
begin
LoadBufferText(NewText);
end;
function TTextBuffer.Trail: string;
begin
if not Empty then
begin
if not EOF then
result := FData.Substring(FOffset, length(FData) );
//result := Copy( FData, FOffset, length(FData) );
end;
end;
procedure TTextBuffer.LoadBufferText(const NewBuffer: string);
begin
// Flush existing buffer
Clear();
// Load in buffertext, init offset and values
var TempLen := NewBuffer.Length;
if TempLen > 0 then
begin
FData := NewBuffer;
FOffset := 0; // start at BOF
FCol := 0;
FRow := 0;
FLength := TempLen;
end;
end;
function TTextBuffer.GetCurrentLocation: TTextBufferBookmark;
begin
if Failed then
ClearLastError();
if not Empty then
begin
result := TTextBufferBookmark.Create;
result.bbOffset := FOffset;
result.bbCol := FCol;
result.bbRow := FRow;
end else
raise ETextBuffer.Create
('Failed to return position, buffer is empty error');
end;
function TTextBuffer.Bookmark: TTextBufferBookmark;
begin
if Failed then
ClearLastError();
if not Empty then
begin
result := TTextBufferBookmark.Create;
result.bbOffset := FOffset;
result.bbCol := FCol;
result.bbRow := FRow;
{$IFDEF USE_BMARK}
FBookmarks.add(result);
{$ENDIF}
end else
raise ETextBuffer.Create
('Failed to bookmark location, buffer is empty error');
end;
procedure TTextBuffer.Restore(const Mark: TTextBufferBookmark);
begin
if Failed then
ClearLastError();
if not Empty then
begin
if Mark nil then
begin
FOffset := Mark.bbOffset;
FCol := Mark.bbCol;
FRow := Mark.bbRow;
Mark.Free;
{$IFDEF USE_BMARK}
var idx := FBookmarks.Count;
if idx > 0 then
begin
dec(idx);
FOffset := FBookmarks[idx].bbOffset;
FCol := FBookmarks[idx].bbCol;
FRow := FBookmarks[idx].bbRow;
FBookmarks.Remove(idx);
//FBookmarks.SetLength(idx)
//FBookmarks.Delete(idx,1);
end else
raise ETextBuffer.Create('Failed to restore bookmark, none exist');
{$ENDIF}
end else
raise ETextBuffer.Create('Failed to restore bookmark, object was nil error');
end else
raise ETextBuffer.Create
('Failed to restore bookmark, buffer is empty error');
end;
{$IFDEF USE_BMARK}
procedure TTextBuffer.Drop;
begin
if Failed then
ClearLastError();
if not Empty then
begin
if FBookmarks.Count > 0 then
FBookmarks.Remove(FBookmarks.Count-1)
else
raise ETextBuffer.Create('Failed to drop bookmark, none exist');
end else
raise ETextBuffer.Create
('Failed to drop bookmark, buffer is empty error');
end;
{$ENDIF}
function TTextBuffer.Read(var Fragment: char): boolean;
begin
if Failed then
ClearLastError();
if not Empty then
begin
result := FOffset <= length(FData);
if result then
begin
// return character
Fragment := FData[FOffset];
// update offset
inc(FOffset)
end else
begin
// return invalid char
Fragment := #0;
// Set error reason
SetLastError('Offset at BOF error');
end;
end else
begin
result := false;
Fragment := #0;
SetLastError('Buffer is empty error');
end;
end;
function TTextBuffer.Read: char;
begin
if Failed then
ClearLastError();
if not Empty then
begin
result := Current;
Next();
end else
result := #0;
end;
function TTextBuffer.ReadToEOL: boolean;
begin
if Failed then
ClearLastError();
if not Empty() then
begin
if BOF() then
begin
if not First() then
exit;
end;
if EOF() then
begin
SetLastError(CNT_ERR_OFFSET_EOF);
exit;
end;
// Keep start
var LStart := FOffset;
// Enum until match of EOF
{$IFDEF USE_INCLUSIVE}
repeat
if (FData[FOffset] = #13)
and (FData[FOffset + 1] = #10) then
begin
result := true;
break;
end else
begin
inc(FOffset);
inc(FCol);
end;
until EOF();
{$ELSE}
While FOffset < High(FData) do
begin
if (FData[FOffset] = #13)
and (FData[FOffset + 1] = #10) then
begin
result := true;
break;
end else
begin
inc(FOffset);
inc(FCol);
end;
end;
{$ENDIF}
// Last line in textfile might not have
// a CR+LF, so we have to check for termination
if not result then
begin
if EOF then
begin
if LStart = Low(FData)) and (FOffset = Low(FData)) and (FOffset = Low(FData)) and (FOffset = Low(FData)) and (FOffset = Low(FData)) and (FOffset = Low(FData)) and (FOffset = Low(FData)) and (FOffset = Low(FData)) and (FOffset = Low(FData)) and (FOffset = Low(FData)) and (FOffset = Low(FData)) and (FOffset = Low(FData)) and (FOffset = Low(FData)) and (FOffset <= high(FData) ) )
and ( (FData[FOffset] = '= Low(FData)) and (FOffset ') );
end;
function TTextBuffer.Equal: boolean;
begin
result := (not Empty)
and ( (FOffset >= Low(FData)) and (FOffset = Low(FData)) and (FOffset = Low(FData)) and (FOffset LStart then
begin
// Any text to return? Or did we start
// directly on a CR+LF and have no text to give?
var LLen := FOffset - LStart;
TextRead := FData.Substring(LStart, LLen);
//TextRead := Copy(FData, LStart, LLen);
end;
// Either way, we exit because CR+LF has been found
result := true;
break;
end;
inc(FOffset);
inc(FCol);
until EOF();
{$ELSE}
While FOffset LStart then
begin
// Any text to return? Or did we start
// directly on a CR+LF and have no text to give?
var LLen := FOffset - LStart;
TextRead := copy(FData, LStart, LLen);
end;
// Either way, we exit because CR+LF has been found
result := true;
break;
end;
inc(FOffset);
inc(FCol);
end;
{$ENDIF}
// Last line in textfile might not have
// a CR+LF, so we have to check for EOF and treat
// that as a terminator.
if not result then
begin
if FOffset >= high(FData) then
begin
if LStart 0 then
begin
TextRead := FData.Substring(LStart, LLen);
//TextRead := Copy(FData, LStart, LLen);
result := true;
end;
exit;
end;
end;
end;
end;
end;
function TTextBuffer.ReadTo(const CB: TTextValidCB; var TextRead: string): boolean;
begin
if Failed then
ClearLastError();
TextRead := '';
if not Empty then
begin
if BOF() then
begin
if not First() then
exit;
end;
if EOF() then
begin
SetLastError(CNT_ERR_OFFSET_EOF);
exit;
end;
if not assigned(CB) then
begin
SetLastError('Invalid callback handler');
exit;
end;
{$IFDEF USE_INCLUSIVE}
repeat
if not CB(Current) then
break
else
TextRead := TextRead + Current;
if not Next() then
break;
until EOF();
{$ELSE}
while not EOF do
begin
if not CB(Current) then
break
else
TextRead := TextRead + Current;
if not Next() then
break;
end;
{$ENDIF}
result := TextRead.Length > 0;
end else
begin
result := false;
SetLastError(CNT_ERR_BUFFER_EMPTY);
end;
end;
function TTextBuffer.ReadTo(const Resignators: TSysCharSet; var TextRead: string): boolean;
begin
if Failed then
ClearLastError();
TextRead := '';
if not Empty then
begin
if BOF() then
begin
if not First() then
exit;
end;
if EOF() then
begin
SetLastError(CNT_ERR_OFFSET_EOF);
exit;
end;
{$IFDEF USE_INCLUSIVE}
repeat
if not Resignators.Contains(Current) then
TextRead := TextRead + Current
else
break;
if not Next() then
break;
until EOF();
{$ELSE}
while not EOF do
begin
if not (Current in Resignators) then
TextRead := TextRead + Current
else
break;
if not Next() then
break;
end;
{$ENDIF}
result := TextRead.Length > 0;
end else
begin
result := false;
SetLastError(CNT_ERR_BUFFER_EMPTY);
end;
end;
function TTextBuffer.ReadTo(MatchText: string): boolean;
begin
if Failed then
ClearLastError();
if not Empty() then
begin
if BOF() then
begin
if not First() then
exit;
end;
if EOF() then
begin
SetLastError(CNT_ERR_OFFSET_EOF);
exit;
end;
var MatchLen := length(MatchText);
if MatchLen > 0 then
begin
MatchText := MatchText.ToLower();
repeat
var TempCache := '';
if Peek(MatchLen, TempCache) then
begin
TempCache := TempCache.ToLower();
result := SameText(TempCache, MatchText);
if result then
break;
end;
if not Next then
break;
until EOF;
end;
end else
begin
result := false;
SetLastError(CNT_ERR_BUFFER_EMPTY);
end;
end;
function TTextBuffer.ReadTo(MatchText: string; var TextRead: string): boolean;
begin
if Failed then
ClearLastError();
result := false;
TextRead := '';
if not Empty() then
begin
if BOF() then
begin
if not First() then
exit;
end;
if EOF() then
begin
SetLastError(CNT_ERR_OFFSET_EOF);
exit;
end;
if MatchText.Length > 0 then
begin
MatchText := MatchText.ToLower();
repeat
var TempCache := '';
if Peek(MatchText.Length, TempCache) then
begin
TempCache := TempCache.ToLower();
result := SameText(TempCache, MatchText);
if result then
break
else
TextRead := TextRead + Current;
end else
TextRead := TextRead + Current;
if not Next() then
break;
until EOF;
end;
end else
begin
result := false;
SetLastError(CNT_ERR_BUFFER_EMPTY);
end;
end;
procedure TTextBuffer.Inject(const TextToInject: string);
begin
if length(FData) > 0 then
begin
var lSeg1 := FData.Substring(1, FOffset);
var lSeg2 := FData.Substring(FOffset + 1, length(FData));
//var LSeg1 := Copy(FData, 1, FOffset);
//var LSeg2 := Copy(FData, FOffset+1, FData.Length);
FData := lSeg1 + TextToInject + lSeg2;
end else
FData := TextToInject;
end;
function TTextBuffer.Compare(const CompareText: string;
const CaseSensitive: boolean): boolean;
begin
if Failed then
ClearLastError();
if not Empty() then
begin
if BOF() then
begin
if not First() then
exit;
end;
if EOF() then
begin
SetLastError(CNT_ERR_OFFSET_EOF);
exit;
end;
var LenToRead := CompareText.Length;
if LenToRead > 0 then
begin
// Peek will set an error message if it
// fails, so we dont need to set anything here
var ReadData := '';
if Peek(LenToRead, ReadData) then
begin
case CaseSensitive of
false: result := ReadData.ToLower() = CompareText.ToLower();
true: result := ReadData = CompareText;
end;
end;
end else
SetLastError(CNT_ERR_LENGTH_INVALID);
end else
SetLastError(CNT_ERR_BUFFER_EMPTY);
end;
procedure TTextBuffer.ConsumeJunk;
begin
if Failed then
ClearLastError();
if not Empty then
begin
if BOF() then
begin
if not First() then
exit;
end;
if EOF() then
begin
SetLastError(CNT_ERR_OFFSET_EOF);
exit;
end;
repeat
case Current of
' ':
begin
end;
'"':
begin
break;
end;
#8, #09:
begin
end;
'/':
begin
(* Skip C style remark *)
if Compare('/*', false) then
begin
if ReadTo('*/') then
begin
inc(FOffset, 2);
Continue;
end else
SetLastError(CNT_ERR_COMMENT_NOTCLOSED);
end else
begin
(* Skip Pascal style remark *)
if Compare('//', false) then
begin
if ReadToEOL() then
begin
continue;
end else
SetLastError(CNT_ERR_OFFSET_EXPECTED_EOF);
end;
end;
end;
'(':
begin
(* Skip pascal style remark *)
if Compare('(*', false)
and not Compare('(*)', false) then
begin
if ReadTo('*)') then
begin
inc(FOffset, 2);
continue;
end else
SetLastError(CNT_ERR_COMMENT_NOTCLOSED);
end else
break;
end;
#13:
begin
if FData[FOffset + 1] = #10 then
inc(FOffset, 2)
else
inc(FOffset, 1);
//if Peek = #10 then
// ConsumeCRLF;
continue;
end;
#10:
begin
inc(FOffset);
continue;
end;
else
break;
end;
if not Next() then
break;
until EOF;
end else
SetLastError(CNT_ERR_BUFFER_EMPTY);
end;
procedure TTextBuffer.ConsumeCRLF;
begin
if not Empty then
begin
if BOF() then
begin
if not First() then
exit;
end;
if EOF() then
begin
SetLastError(CNT_ERR_OFFSET_EOF);
exit;
end;
if (FData[FOffset] = #13) then
begin
if FData[FOffset + 1] = #10 then
inc(FOffset, 2)
else
inc(FOffset);
inc(FRow);
FCol := 0;
end;
end;
end;
function TTextBuffer.Empty: boolean;
begin
result := FLength < 1;
end;
// This method will look ahead, skipping space, tab and crlf (also known
// as control characters), and when a non control character is found it will
// perform a string compare. This method uses a bookmark and will restore
// the offset to the same position as when it was entered.
//
// Notes: The method "NextNonControlChar" is a similar method that
// performs a char-only compare.
function TTextBuffer.NextNonControlText(const CompareWith: string): boolean;
begin
if Failed then
ClearLastError();
if not Empty then
begin
if BOF() then
begin
if not First() then
exit;
end;
if EOF() then
begin
SetLastError(CNT_ERR_OFFSET_EOF);
exit;
end;
var Mark := Bookmark();
try
// Iterate ahead
repeat
if not (Current in [' ', #13, #10, #09]) then
break;
Next();
until EOF();
// Compare unless we hit the end of the line
if not EOF then
result := Compare(CompareWith, false);
finally
Restore(Mark);
end;
end else
SetLastError(CNT_ERR_BUFFER_EMPTY);
end;
// This method will look ahead, skipping space, tab and crlf (also known
// as control characters), and when a non control character is found it will
// perform a string compare. This method uses a bookmark and will restore
// the offset to the same position as when it was entered.
function TTextBuffer.NextNonControlChar(const CompareWith: char): boolean;
begin
if Failed then
ClearLastError();
if not Empty then
begin
if BOF() then
begin
if not First() then
exit;
end;
if EOF() then
begin
SetLastError(CNT_ERR_OFFSET_EOF);
exit;
end;
var Mark := Bookmark();
try
repeat
if not (Current in [' ', #13, #10, #09]) then
break;
Next();
until EOF();
//if not EOF then
result := Current.ToLower() = CompareWith.ToLower();
//result := LowerCase(Current) = LowerCase(CompareWith);
finally
Restore(Mark);
end;
end else
SetLastError(CNT_ERR_BUFFER_EMPTY);
end;
function TTextBuffer.Peek: char;
begin
if Failed then
ClearLastError();
if not Empty then
begin
if (FOffset 0 do
begin
TextRead := TextRead + Current;
if not Next() then
break;
dec(CharCount);
end;
finally
Restore(Mark);
end;
result := TextRead.Length > 0;
end else
SetLastError(CNT_ERR_OFFSET_EOF);
end else
SetLastError(CNT_ERR_BUFFER_EMPTY);
end;
function TTextBuffer.First: boolean;
begin
if Failed then
ClearLastError();
if not Empty then
begin
FOffset := Low(FData);
result := true;
end else
SetLastError(CNT_ERR_BUFFER_EMPTY);
end;
function TTextBuffer.Last: boolean;
begin
if Failed then
ClearLastError();
if not Empty then
begin
FOffset := high(FData);
result := true;
end else
SetLastError(CNT_ERR_BUFFER_EMPTY);
end;
function TTextBuffer.NextNoCrLf: boolean;
begin
if Failed then
ClearLastError();
if not Empty then
begin
// Check that we are not EOF
result := FOffset <= high(FData);
if result then
begin
// Update offset into buffer
inc(FOffset);
// update column, but not if its in a lineshift
if not (FData[FOffset] in [#13, #10]) then
inc(FCol);
end else
SetLastError(CNT_ERR_OFFSET_EOF);
end else
SetLastError(CNT_ERR_BUFFER_EMPTY);
end;
function TTextBuffer.Next: boolean;
begin
if Failed then
ClearLastError();
if not Empty() then
begin
if BOF() then
begin
if not First() then
exit;
end;
if EOF() then
begin
SetLastError(CNT_ERR_OFFSET_EOF);
exit;
end;
// Update offset into buffer
inc(FOffset);
// update column
inc(FCol);
// This is the same as ConsumeCRLF
// But this does not generate any errors since we PEEK
// ahead into the buffer to make sure the combination
// is correct before we adjust the ROW + offset
if FOffset Low(FData));
if result then
dec(FOffset)
else
SetLastError(CNT_ERR_OFFSET_BOF);
end else
SetLastError(CNT_ERR_BUFFER_EMPTY);
end;
function TTextBuffer.Current: char;
begin
if Failed then
ClearLastError();
// Check that buffer is not empty
if not Empty then
begin
// Check that we are on char 1 or more
if FOffset >= Low(FData) then
begin
// Check that we are before or on the last char
if (FOffset <= high(FData)) then
result := FData[FOffset]
else
begin
SetLastError(CNT_ERR_OFFSET_EOF);
result := #0;
end;
end else
begin
SetLastError(CNT_ERR_OFFSET_BOF);
result := #0;
end;
end else
begin
SetLastError(CNT_ERR_BUFFER_EMPTY);
result := #0;
end;
end;
function TTextBuffer.BOF: boolean;
begin
if not Empty then
result := FOffset high(FData);
end;
function TTextBuffer.NextLine: boolean;
begin
if Failed then
ClearLastError();
if not Empty then
begin
// Make sure we offset to a valid character
// in the buffer.
ConsumeJunk();
if not EOF then
begin
var ThisRow := self.FRow;
while Row = ThisRow do
begin
Next();
if EOF then
break;
end;
result := (Row ThisRow) and (not EOF);
end;
end;
end;
function TTextBuffer.ReadWord(var TextRead: string): boolean;
begin
if Failed then
ClearLastError();
TextRead := '';
if not Empty then
begin
// Make sure we offset to a valid character
// in the buffer.
ConsumeJunk();
// Not at the end of the file?
if not EOF then
begin
repeat
var el := Current;
if (el in
[ 'A'..'Z',
'a'..'z',
'0'..'9',
'_', '-' ]) then
TextRead := TextRead + el
else
break;
if not NextNoCrLf() then
break;
until EOF;
result := TextRead.Length > 0;
end else
SetLastError('Failed to read word, unexpected EOF');
end else
SetLastError('Failed to read word, buffer is empty error');
end;
function TTextBuffer.ReadCommaList(var cList: List): boolean;
var
LTemp: String;
LValue: String;
begin
if cList = nil then
cList := new List
else
cList.Clear();
if not Empty then
begin
ConsumeJunk();
While not EOF do
begin
case Current of
#09:
begin
// tab, just skip
end;
#13, #10:
begin
// CR+LF, consume and continue;
ConsumeCRLF();
end;
#0:
begin
// Unexpected EOL
break;
end;
';':
begin
//Perfectly sound ending
result := true;
break;
end;
'"':
begin
LValue := ReadQuotedString;
if LValue.Length > 0 then
begin
cList.add(LValue);
LValue := '';
end;
end;
',':
begin
LTemp := LTemp.Trim();
if LTemp.Length>0 then
begin
cList.add(LTemp);
LTemp := '';
end;
end;
else
begin
LTemp := LTemp + Current;
end;
end;
if not Next() then
break;
end;
if LTemp.Length > 0 then
cList.add(LTemp);
result := cList.Count > 0;
end;
end;
function TTextBuffer.ReadQuotedString: string;
begin
if not Empty then
begin
if not EOF then
begin
// Make sure we are on the " entry quote
if Current '"' then
begin
SetLastError('Failed to read quoted string, expected index on " character error');
exit;
end;
// Skip the entry char
if not NextNoCrLf() then
begin
SetLastError('Failed to skip initial " character error');
exit;
end;
while not EOF do
begin
// Read char from buffer
var TempChar := Current;
// Closing of string? Exit
if TempChar = '"' then
begin
if not NextNoCrLf then
SetLastError('failed to skip final " character in string error');
break;
end;
result := result + TempChar;
if not NextNoCrLf() then
break;
end;
end;
end;
end;
//##########################################################################
// TParserModelObject
//##########################################################################
constructor TParserModelObject.Create(const AParent:TParserModelObject);
begin
inherited Create;
FParent := AParent;
FChildren := new List;
end;
function TParserModelObject.GetParent:TParserModelObject;
begin
result := FParent;
end;
procedure TParserModelObject.Clear;
begin
FChildren.Clear();
end;
function TParserModelObject.ChildGetCount: integer;
begin
result := FChildren.Count;
end;
function TParserModelObject.ChildGetItem(const Index: integer): TParserModelObject;
begin
result := TParserModelObject(FChildren[Index]);
end;
function TParserModelObject.ChildAdd(const Instance: TParserModelObject): TParserModelObject;
begin
if FChildren.IndexOf(Instance) < 0 then
FChildren.add(Instance);
result := Instance;
end;
//###########################################################################
// TParserContext
//###########################################################################
constructor TParserContext.Create(const SourceCode: string);
begin
inherited Create;
FBuffer := TTextBuffer.Create(SourceCode);
FStack := new Stack;
end;
procedure TParserContext.Push(const ModelObj: TParserModelObject);
begin
if Failed then
ClearLastError();
try
FStack.Push(ModelObj);
except
on e: Exception do
SetLastError('Internal error:' + e.Message);
end;
end;
function TParserContext.Pop: TParserModelObject;
begin
if Failed then
ClearLastError();
try
result := FStack.Pop();
except
on e: Exception do
SetLastError('Internal error:' + e.Message);
end;
end;
function TParserContext.Peek: TParserModelObject;
begin
if Failed then
ClearLastError();
try
result := FStack.Peek();
except
on e: Exception do
SetLastError('Internal error:' + e.Message);
end;
end;
procedure TParserContext.ClearStack;
begin
if Failed then
ClearLastError();
try
FStack.Clear();
except
on e: Exception do
SetLastError('Internal error:' + e.Message);
end;
end;
//###########################################################################
// TCustomParser
//###########################################################################
constructor TCustomParser.Create(const ParseContext: TParserContext);
begin
inherited Create;
FContext := ParseContext;
end;
function TCustomParser.Parse: boolean;
begin
result := false;
SetLastErrorF('No parser implemented for class %s',[ClassName]);
end;
procedure TCustomParser.SetContext(const NewContext: TParserContext);
begin
FContext := NewContext;
end;
end.
Generic protect for FPC/Lazarus
Freepascal is not frequently mentioned on my blog. I have written about it from time to time, not always in a positive light though. Just to be clear, FPC (the compiler) is fantastic; it was one particular fork of Lazarus I had issues with, involving a license violation.
On the whole, freepascal and Lazarus is capable of great things. There are a few quirks here and there (if not oddities) that prevents mass adoption (the excessive use of include-files to “fake” partial classes being one), but as object-pascal compilers go, Freepascal is a battle-hardened, production ready system.
It’s been Linux in particular that I have used Freepascal on. In 2015 Hydro Oil wanted to move their back-end from Windows to Linux, and I spent a few months converting windows-only services into Linux daemons.
Today I find myself converting parts of the toolkit I came up with to Oxygene, but that’s a post for another day.
Generic protect
If you work a lot with multithreaded code, the unit im posting here might come in handy. Long story short: sharing composite objects between threads and the main process, always means extra scaffolding. You have to make sure you don’t access the list (or it’s elements) at the same time as another thread for example. To ensure this you can either use a critical-section, or you can deliver the data with a synchronized call. This is more or less universal for all languages, no matter if you are using Oxygene, C/C++, C# or Delphi.
When this unit came into being, I was doing quite elaborate classes with a lot of lists. These classes could not share ancestor, or I could have gotten away with just one locking mechanism. Instead I had to implement the same boilerplate code over and over again.
The unit below makes insulating (or protecting) classes easier. It essentially envelopes whatever class-instance you feed it, and returns the proxy object. Whenever you want to access your instance, you have to unlock it first or use a synchronizer (see below).
Works in both Freepascal and Delphi
The unit works for both Delphi and Freepascal, but there is one little difference. For some reason Freepascal does not support anonymous procedures, so we compensate and use inline-procedures instead. While not a huge deal, I really hope the FPC team add anonymous procedures, it makes life a lot easier for generics based code. Async programming without anonymous procedures is highly impractical too.
So if you are in Delphi you can write:
var lValue: TProtectedValue; lValue.Synchronize( procedure (var Value: integer) begin Value := Value * 12; end);
But under Freepascal you must resort to:
var lValue: TProtectedValue; procedure _UpdateValue(var Data: integer); begin Data := Data * 12; end; begin lValue.Synchronize(@_UpdateValue); end;
On small examples like these, the benefit of this style of coding might be lost; but if you suddenly have 40-50 lists that needs to be shared between 100-200 active threads, it will be a time saver!
You can also use it on intrinsic datatypes:
OK, here we go:
unit safeobjects;
// SafeObjects
// ==========================================================================
// Written by Jon-Lennart Aasenden
// Copyright Quartex Components LTD, all rights reserved
//
// This unit is a part of the QTX Patreon Library
//
// NOTES ABOUT FREEPASCAL:
// =======================
// Freepascal does not allow anonymous procedures, which means we must
// resort to inline procedures instead:
//
// Where we in Delphi could write the following for an atomic,
// thread safe alteration:
//
// var
// LValue: TProtectedValue;
//
// LValue.Synchronize( procedure (var Value: integer)
// begin
// Value := Value * 12;
// end);
//
// Freepascal demands that we use an inline procedure instead, which
// is more or less the same code, just organized slightly differently.
//
// var
// LValue: TProtectedValue;
//
// procedure _UpdateValue(var Data: integer);
// begin
// Data := Data * 12;
// end;
//
// begin
// LValue.Synchronize(@_UpdateValue);
// end;
//
//
//
//
{$mode DELPHI}
{$H+}
interface
uses
{$IFDEF FPC}
SysUtils,
Classes,
SyncObjs,
Generics.Collections;
{$ELSE}
System.SysUtils,
System.Classes,
System.SyncObjs,
System.Generics.Collections;
{$ENDIF}
type
{$DEFINE INHERIT_FROM_CRITICALSECTION}
TProtectedValueAccessRights = set of (lvRead, lvWrite);
EProtectedValue = class(exception);
EProtectedObject = class(exception);
(* Thread safe intrinsic datatype container.
When sharing values between processes, use this class
to make read/write access safe and protected. *)
{$IFDEF INHERIT_FROM_CRITICALSECTION}
TProtectedValue = class(TCriticalSection)
{$ELSE}
TProtectedValue = class(TObject)
{$ENDIF}
strict private
{$IFNDEF INHERIT_FROM_CRITICALSECTION}
FLock: TCriticalSection;
{$ENDIF}
FData: T;
FOptions: TProtectedValueAccessRights;
strict protected
function GetValue: T;virtual;
procedure SetValue(Value: T);virtual;
function GetAccessRights: TProtectedValueAccessRights;
procedure SetAccessRights(Rights: TProtectedValueAccessRights);
public
type
{$IFDEF FPC}
TProtectedValueEntry = procedure (var Data: T);
{$ELSE}
TProtectedValueEntry = reference to procedure (var Data: T);
{$ENDIF}
public
constructor Create(Value: T); overload; virtual;
constructor Create(Value: T; const Access: TProtectedValueAccessRights); overload; virtual;
constructor Create(const Access: TProtectedValueAccessRights); overload; virtual;
destructor Destroy;override;
{$IFNDEF INHERIT_FROM_CRITICALSECTION}
procedure Enter;
procedure Leave;
{$ENDIF}
procedure Synchronize(const Entry: TProtectedValueEntry);
property AccessRights: TProtectedValueAccessRights read GetAccessRights;
property Value: T read GetValue write SetValue;
end;
(* Thread safe object container.
NOTE #1: This object container **CREATES** the instance and maintains it!
Use Edit() to execute a protected block of code with access
to the object.
Note #2: SetValue() does not overwrite the object reference, but
attempts to perform TPersistent.Assign(). If the instance
does not inherit from TPersistent an exception is thrown. *)
TProtectedObject = class(TObject)
strict private
FData: T;
FLock: TCriticalSection;
FOptions: TProtectedValueAccessRights;
strict protected
function GetValue: T;virtual;
procedure SetValue(Value: T);virtual;
function GetAccessRights: TProtectedValueAccessRights;
procedure SetAccessRights(Rights: TProtectedValueAccessRights);
public
type
{$IFDEF FPC}
TProtectedObjectEntry = procedure (const Data: T);
{$ELSE}
TProtectedObjectEntry = reference to procedure (const Data: T);
{$ENDIF}
public
property Value: T read GetValue write SetValue;
property AccessRights: TProtectedValueAccessRights read GetAccessRights;
function Lock: T;
procedure Unlock;
procedure Synchronize(const Entry: TProtectedObjectEntry);
Constructor Create(const AOptions: TProtectedValueAccessRights = [lvRead,lvWrite]); virtual;
Destructor Destroy; override;
end;
(* TProtectedObjectList:
This is a thread-safe object list implementation.
It works more or less like TThreadList, except it deals with objects *)
TProtectedObjectList = class(TInterfacedPersistent)
strict private
FObjects: TObjectList;
FLock: TCriticalSection;
strict protected
function GetEmpty: boolean;virtual;
function GetCount: integer;virtual;
(* QueryObject Proxy: TInterfacedPersistent allows us to
act as a proxy for QueryInterface/GetInterface. Override
and provide another child instance here to expose
interfaces from that instread *)
protected
function GetOwner: TPersistent;override;
public
type
{$IFDEF FPC}
TProtectedObjectListProc = procedure (Item: TObject; var Cancel: boolean);
{$ELSE}
TProtectedObjectListProc = reference to procedure (Item: TObject; var Cancel: boolean);
{$ENDIF}
public
constructor Create(OwnsObjects: Boolean = true); virtual;
destructor Destroy; override;
function Contains(Instance: TObject): boolean; virtual;
function Enter: TObjectList; virtual;
Procedure Leave; virtual;
Procedure Clear; virtual;
procedure ForEach(const CB: TProtectedObjectListProc); virtual;
Property Count: integer read GetCount;
Property Empty: boolean read GetEmpty;
end;
implementation
//############################################################################
// TProtectedObjectList
//############################################################################
constructor TProtectedObjectList.Create(OwnsObjects: Boolean = True);
begin
inherited Create;
FObjects := TObjectList.Create(OwnsObjects);
FLock := TCriticalSection.Create;
end;
destructor TProtectedObjectList.Destroy;
begin
FLock.Enter;
FObjects.Free;
FLock.Free;
inherited;
end;
procedure TProtectedObjectList.Clear;
begin
FLock.Enter;
try
FObjects.Clear;
finally
FLock.Leave;
end;
end;
function TProtectedObjectList.GetOwner: TPersistent;
begin
result := NIL;
end;
procedure TProtectedObjectList.ForEach(const CB: TProtectedObjectListProc);
var
LItem: TObject;
LCancel: Boolean;
begin
LCancel := false;
if assigned(CB) then
begin
FLock.Enter;
try
{$HINTS OFF}
for LItem in FObjects do
begin
LCancel := false;
CB(LItem, LCancel);
if LCancel then
break;
end;
{$HINTS ON}
finally
FLock.Leave;
end;
end;
end;
function TProtectedObjectList.Contains(Instance: TObject): boolean;
begin
result := false;
if assigned(Instance) then
begin
FLock.Enter;
try
result := FObjects.Contains(Instance);
finally
FLock.Leave;
end;
end;
end;
function TProtectedObjectList.GetCount: integer;
begin
FLock.Enter;
try
result :=FObjects.Count;
finally
FLock.Leave;
end;
end;
function TProtectedObjectList.GetEmpty: Boolean;
begin
FLock.Enter;
try
result := FObjects.Count<1;
finally
FLock.Leave;
end;
end;
function TProtectedObjectList.Enter: TObjectList;
begin
FLock.Enter;
result := FObjects;
end;
procedure TProtectedObjectList.Leave;
begin
FLock.Leave;
end;
//############################################################################
// TProtectedObject
//############################################################################
constructor TProtectedObject.Create(const AOptions: TProtectedValueAccessRights = [lvRead, lvWrite]);
begin
inherited Create;
FLock := TCriticalSection.Create;
FLock.Enter();
try
FOptions := AOptions;
FData := T.Create;
finally
FLock.Leave();
end;
end;
destructor TProtectedObject.Destroy;
begin
FData.free;
FLock.Free;
inherited;
end;
function TProtectedObject.GetAccessRights: TProtectedValueAccessRights;
begin
FLock.Enter;
try
result := FOptions;
finally
FLock.Leave;
end;
end;
procedure TProtectedObject.SetAccessRights(Rights: TProtectedValueAccessRights);
begin
FLock.Enter;
try
FOptions := Rights;
finally
FLock.Leave;
end;
end;
function TProtectedObject.Lock: T;
begin
FLock.Enter;
result := FData;
end;
procedure TProtectedObject.Unlock;
begin
FLock.Leave;
end;
procedure TProtectedObject.Synchronize(const Entry: TProtectedObjectEntry);
begin
if assigned(Entry) then
begin
FLock.Enter;
try
Entry(FData);
finally
FLock.Leave;
end;
end;
end;
function TProtectedObject.GetValue: T;
begin
FLock.Enter;
try
if (lvRead in FOptions) then
result := FData
else
raise EProtectedObject.CreateFmt('%s:Read not allowed error',[classname]);
finally
FLock.Leave;
end;
end;
procedure TProtectedObject.SetValue(Value: T);
begin
FLock.Enter;
try
if (lvWrite in FOptions) then
begin
if (TObject(FData) is TPersistent)
or (TObject(FData).InheritsFrom(TPersistent)) then
TPersistent(FData).Assign(TPersistent(Value))
else
raise EProtectedObject.CreateFmt
('Locked object assign failed, %s does not inherit from %s',
[TObject(FData).ClassName,'TPersistent']);
end else
raise EProtectedObject.CreateFmt('%s:Write not allowed error',[classname]);
finally
FLock.Leave;
end;
end;
//############################################################################
// TProtectedValue
//############################################################################
Constructor TProtectedValue.Create(const Access: TProtectedValueAccessRights);
begin
inherited Create;
{$IFNDEF INHERIT_FROM_CRITICALSECTION}
FLock := TCriticalSection.Create;
{$ENDIF}
FOptions := Access;
end;
constructor TProtectedValue.Create(Value: T);
begin
inherited Create;
{$IFNDEF INHERIT_FROM_CRITICALSECTION}
FLock := TCriticalSection.Create;
{$ENDIF}
FOptions := [lvRead, lvWrite];
FData := Value;
end;
constructor TProtectedValue.Create(Value: T; const Access: TProtectedValueAccessRights);
begin
inherited Create;
{$IFNDEF INHERIT_FROM_CRITICALSECTION}
FLock := TCriticalSection.Create;
{$ENDIF}
FOptions := Access;
FData := Value;
end;
Destructor TProtectedValue.Destroy;
begin
{$IFNDEF INHERIT_FROM_CRITICALSECTION}
FLock.Free;
{$ENDIF}
inherited;
end;
function TProtectedValue.GetAccessRights: TProtectedValueAccessRights;
begin
Enter();
try
result := FOptions;
finally
Leave();
end;
end;
procedure TProtectedValue.SetAccessRights(Rights: TProtectedValueAccessRights);
begin
Enter();
try
FOptions := Rights;
finally
Leave();
end;
end;
{$IFNDEF INHERIT_FROM_CRITICALSECTION}
procedure TProtectedValue.Enter;
begin
FLock.Enter;
end;
procedure TProtectedValue.Leave;
begin
FLock.Leave;
end;
{$ENDIF}
procedure TProtectedValue.Synchronize(const Entry: TProtectedValueEntry);
begin
if assigned(Entry) then
Begin
Enter();
try
Entry(FData);
finally
Leave();
end;
end;
end;
function TProtectedValue.GetValue: T;
begin
Enter();
try
if (lvRead in FOptions) then
result := FData
else
raise EProtectedValue.CreateFmt('%s: Read not allowed error', [Classname]);
finally
Leave();
end;
end;
procedure TProtectedValue.SetValue(Value: T);
begin
Enter();
try
if (lvWrite in FOptions) then
FData:=Value
else
raise EProtectedValue.CreateFmt('%s: Write not allowed error', [Classname]);
finally
Leave();
end;
end;
end.
Raspberry PI 4 at last!
It was with astonishment that I opened up my browser this morning to read some daily IT news, only to discover that the Raspberry PI v4 has finally arrived! And boy what a landslide update to the 3.x family it is!
Three times the fun
There are plenty of sites that entertains page-up and page-down with numbers, but I will save all that for an article where I have the physical kit in my posession. But looking at the preliminaries I think it’s safe to say that we are looking at a solid 3x the speed of the older yet capable PI 3b+.
The PI returns, and what a joy it is!
While the 3x speed boost is enough to bump the SoC up, from entertaining to serious for business applications – it’s ultimately the memory footprint that will make all the difference. While the Raspberry PI is probably the most loved SBC (single board computer) of all time, it’s always been cut short due to lack of memory. 512 megabyte can only do so much in 2019, and even the slimmest of Linux distributions quickly consumes more ram that older versions could supply.
VideoCore 6, two screens and 4k video
The new model ships in three different configurations, with 1, 2 and 4 gigabytes of ram respectively. I strongly urge people to get the 4Gb version, because with that amount of memory coupled with a good solid-state-disk, means you can enable a proper swap-partition. No matter how fast a SoC might be, without memory to compliment it – the system simply wont be able to deliver on its potential. But with 4Gb, a nice solid state disk (just use a SSD-To-USB with one of the sexy new USB 3.x ports) and you are looking at an OK mini-computer capable of most desktop applications.
I have to admit I never expected the PI to ship with support for two monitors, but lo-and-behold, the board has two mini-hdmi out ports! The board is also fitted with the VideCore 6 rather than VideoCore 4.
Not missing the boat with Oxygene and Elements
One of the most frustrating episodes in the history of Delphi, is that we never got a Delphi edition that could target Raspberry PI (or ARM-Linux in general). It was especially frustrating since Allen Bauer actually demonstrated Delphi generating code that ran on a PI in 2012. The result of not directly supporting the PI, even on service level without a UI layer – is that Delphi developers have missed the IOT market completely.
Before Delphi developers missed the IOT revolution, Delphi also missed out on iOS and Android. By the time Delphi developers could target any of these platforms, the market was completely saturated, and all opportunities to make money was long gone. In other words, Delphi has missed the boat on 3 revolutionary platforms in a row. Something which is borderline unforgivable.
The good news though is that Oxygene, the object-pascal compiler from RemObjects, supports the Raspberry PI SoC. I have yet to test this on v4, but since the PI v4 is 100% backwards compatible I don’t see any reason why there should be any issues. The code generated by Oxygene is not bound to just the PI either. As long as it runs on a debian based distro, it should run just fine on most ARM-Linux SoC’s that have working drivers.
And like I have written about elsewhere, you can also compile for WebAssembly, running either in node.js or in the browser — so there are plenty of ways to get your products over!
Stay tuned for the lineup
This week im going to do a lot of testing on various ARM devices to find out just how many SBC’s Oxygene can target, starting with the ODroid N2. But for Raspberry PI, that should be a slam-dunk. Meaning that object-pascal developers can finally make use of affordable off-the-shelves parts in their hardware projects.
As of writing im preparing the various boards I will be testing. We have the PI 3b+, the Tinkerboard from ASUS, NanoPI, Dragonboard, Odroid XU4 – and the latest power-board, the ODroid N2. Out of these offerings only the N2 is en-par with the Raspberry PI v4, although I suspect the Videocore 6 GPU will outperform the Mali G52.
Hydra now supports Freepascal and Java
In case you guys missed it, RemObjects Hydra 6.2 now supports FreePascal!
This means that you can now use forms and units from .net and Java from your Freepascal applications – and (drumroll) also mix and match between Delphi, .net, Java and FPC modules! So if you see something cool that Freepascal lacks, just slap it in a Hydra module and you can use it across language barriers.
I have used Hydra for years with Delphi, and being able to use .net forms and components in Delphi is pretty awesome. It’s also a great framework for building modular applications that are easier to manage.
Being able to tap into Freepascal is a great feature. Or the other way around, with Freepascal showing forms from Delphi, .net or Java.
For example, if you are moving to Freepascal, you can isolate the forms or controls that are not available under Freepascal in a Hydra module, and voila – you can gradually migrate.
If you are moving to Oxygene Pascal the same applies, you can implement the immediate logic under .net, and then import and use the parts that can’t easily be ported (or that you want to wait with).
The best of four worlds — You gotta love that!
Check out Hydra here:
RemObjects VCL, mind blown!
For a guy that spends most of his time online, and can talk for hours about the most nerdy topics known to mankind – being gobsmacked and silenced is a rare event. But this morning that was exactly what happened.
Now, Marc Hoffman has blogged regularly over the years regarding the evolution of the RemObjects toolchain; explaining how they decoupled the parts that make up a programming language, such as syntax, rtl and target, but I must admit haven’t really digested the full implications of that work.
Like most developers I have kept my eyes on the parts relevant for me, like the Remoting SDK, Data Abstract and Javascript support. Before I worked at Embarcadero I pretty much spent 10 years contracting -and building Smart Mobile Studio on the side together with the team at The Smart Company Inc.
Smart Pascal gained support for RemObjects SDK servers quite early
Since both the Remoting SDK and Data Abstract were part of our toolbox as Delphi developers, those were naturally more immediate than anything else. We also added support for RemObjects Remoting SDK inside Smart Mobile Studio, so that people could call existing services from their Javascript applications.
Oxygene then
Like most Delphi developers I remember testing Oxygene Pascal when I bought Delphi 2005. Back then Oxygene was licensed by Borland under the “Prism” name and represented their take on dot net support. I was very excited when it came out, but since my knowledge of the dot net framework was nil, I was 100% relient on the documentation.
In many ways Oxygene was a victim of Rad Studio’s abhorrent help-file system. Documentation for Rad Studio (especially Delphi) up to that point had been exemplary since Delphi 4; but by the time Rad Studio 2005 came out, the bloat had reached epic levels. Even for me as a die-hard Delphi fanatic, Delphi 2005 and 2006 was a tragic experience.
Removing Oxygene was a monumental mistake
I mean, when it takes 15 minutes (literally) just to open the docs, then learning a whole new programming paradigm under those conditions was quite frankly impossible. Like most Delphi developers I was used to Delphi 7 style documentation, where the docs were not just reference material – but actually teaches you the language itself.
In the end Oxygene remained very interesting, but with a full time job, deadlines and kids to take care of, I stuck to what I knew – namely the VCL.
Oxygene today
Just like Delphi has evolved and improved radically since 2005, Oxygene has likewise evolved above and beyond its initial form. Truth be told, we copied a lot of material from Oxygene when we made Smart Pascal, so I feel strangely at home with Oxygene even after a couple of days. The documentation for Oxygene Pascal (and Elements as a whole) is very good: https://docs.elementscompiler.com/Oxygene/
But Oxygene Pascal, while the obvious “first stop” for Delphi developers looking to expand their market impact, is more than “just a language”. It’s a language that is a part of a growing family of languages that RemObjects support and evolve.
As of writing RemObjects offers the following languages. So even if you don’t have a background in Delphi, or perhaps migrated from Delphi to C# years ago – RemObjects will have solutions and benefits to offer:
- Oxygene (object pascal)
- C#
- Swift
- Java
Water is a sexy, slim new IDE for RemObjects languages on Windows. For the OS X version you want to download Fire.
And here is the cool thing: when you hear “Java” you automatically expect that you are bound hands and feet to the Java runtime-libraries right? Same also with C#, you expect C# to be purely limited to the dot-net framework. And if you like me dabbed in Oxygene back in 2005-2006, you probably think Oxygene is purely a dot-net adapted version of Object Pascal right? But RemObjects have turned that on it’s head!
Remember the decoupling I mentioned at the beginning of this post? What that means in practical terms is that they have separated each language into three distinct parts:
- The syntax
- The RTL
- The target
What this means, is that you can pick your own combinations!
Let’s say you are coming from Delphi. You have 20 years of Object Pascal experience under your belt, and while you dont mind learning new things – Object Pascal is where you will be most productive.
Well in that case picking Oxygene Pascal covers the syntax part. But you don’t have to use the dot-net framework if you don’t want to. You can mix and match these 3 parts as you see fit! Let’s look at some combinations you could pick:
- Oxygene Pascal -> dot net framework -> CIL
- Oxygene Pascal -> “VCL” -> CIL
- Oxygene Pascal -> “VCL” -> WinAPI
- Oxygene Pascal -> “VCL” -> WebAssembly
(*) The “VCL” here is a compatibility RTL closely modeled on the Freepascal LCL and Delphi VCL. This is written from scratch and contains no proprietary code. It is purely to get people productive faster.
The whole point of this tripartite decoupling is to allow developers to maximize the value of their existing skill-set. If you know Object Pascal then that is a natural starting point for you. If you know the VCL then obviously the VCL compatibility RTL is going to help you become productive much faster than calling WinAPI on C level. But you can, if you like, go all native. And you can likewise ignore native and opt for WebAssembly.
Sound cool? Indeed it is! But it gets better, let’s look at some of the targets:
- Microsoft Windows
- Apple OS X
- Apple iOS
- Apple WatchOS
- Android
- Android wearables
- Linux x86 / 64
- Linux ARM
- tvOS
- WebAssembly
- * dot-net
- * Java
In short: Pick the language you want, pick the RTL or framework you want, pick the target you want — and start coding!
(*) dot-net and Java are not just frameworks, they are also targets since they are Virtual Machines. WebAssembly also fall under the VM category, although the virtual machine there is bolted into Chrome and Firefox (also node.js).
Some example code
Webassembly is something that interest me more than native these days. Sure I love the speed that native has to offer, but since Javascript has become “the defacto universal platform”, and since most of my work privately is done in Javascript – it seems like the obvious place to start.
Webassembly is a bit like Javascript was 10 years ago. I remember it was a bit of a shock coming from Delphi. We had just created Smart Mobile Studio, and suddenly we realized that the classes and object the browser had to offer were close to barren. We were used to the VCL after all. So my work there was basically to implement something with enough similarity to the VCL to be familiar to to Delphi developer, without wandering too far away from established JS standards.
Webassembly is roughly in the same ballpark. Webassembly is just a runtime engine. It doesn’t give you all those nice and helpful classes out of the box. You are expected to either write that yourself – or (as luck would have it) rely on what language vendors provide.
RemObjects have a lot to offer here, because their “Delphi VCL” compatibility RTL compiles just fine for Webassembly. There is no form designer though, but I haven’t used a form designer in years. I prefer to do everything in code because that’s ultimately what works when your codebase grows large enough anyways. Even my Delphi projects are done mainly as raw code, because I like to have the option to compile with Freepascal and Lazarus.
My first test code for Oxygene Pascal with Webassembly as the target is thus very bare-bone. If there is something that has bugged me to no end, it’s that bloody HTML5 canvas. It’s a powerful thing, but it’s also overkill for per-pixel operations. So I figured that a nice, ad-hoc DIB (device independent bitmap) class will do wonders.
Note: Oxygene supports pointers, even under WebAssembly (!), but out of old habit I have avoided it. I want my code to compile for all the targets, without marking a class as “unsafe” in the dot-net paradigm. So I have avoided pointers and just use offsets instead.
namespace qtxlib;
interface
type
// in-memory pixel format
TPixelFormat = public (
pf8bit = 0, //___8 -- palette indexed
pf15bit = 1, //_555 -- 15 bit encoded
pf16bit = 2, //_565 -- 16 bit encoded
pf24bit = 3, //_888 -- 24 bit native
pf32bit = 4 //888A -- 32 bit native
);
TPixelBuffer = public class
private
FPixels: array of Byte;
FDepthLUT: array of Integer;
FScanLUT: array of Integer;
FStride: Integer;
FWidth: Integer;
FHeight: Integer;
FBytes: Integer;
FFormat: TPixelFormat;
protected
function CalcStride(const Value, PixelByteSize, AlignSize: Integer): Integer;
function GetEmpty: Boolean;
public
property Width: Integer read FWidth;
property Height: Integer read FHeight;
property Stride: Integer read FStride;
property &Empty: Boolean read GetEmpty;
property BufferSize: Integer read FBytes;
property PixelFormat: TPixelFormat read FFormat;
property Buffer[const index: Integer]: Byte read (FPixels[&index]) write (FPixels[&index]);
function OffsetForPixel(const dx, dy: Integer): Integer;
procedure Alloc(NewWidth, NewHeight: Integer; const PxFormat: TPixelFormat);
procedure Release();
function Read(Offset: Integer; ByteLength: Integer): array of Byte;
procedure Write(Offset: Integer; const Data: array of Byte);
constructor Create; virtual;
finalizer;
begin
if not GetEmpty() then
Release();
end;
end;
TColorMixer = public class
end;
TPainter = public class
private
FBuffer: TPixelBuffer;
public
property PixelBuffer: TPixelBuffer read FBuffer;
constructor Create(const PxBuffer: TPixelBuffer); virtual;
end;
implementation
//##################################################################################
// TPainter
//##################################################################################
constructor TPainter.Create(const PxBuffer: TPixelBuffer);
begin
inherited Create();
if PxBuffer nil then
FBuffer := PxBuffer
else
raise new Exception("Pixelbuffer cannot be NIL error");
end;
//##################################################################################
// TPixelBuffer
//##################################################################################
constructor TPixelBuffer.Create;
begin
inherited Create();
FDepthLUT := [1, 2, 2, 3, 4];
end;
function TPixelBuffer.GetEmpty: Boolean;
begin
result := length(FPixels) = 0;
end;
function TPixelBuffer.OffsetForPixel(const dx, dy: integer): Integer;
begin
if length(FPixels) > 0 then
begin
result := dy * FStride;
inc(result, dx * FDepthLUT[FFormat]);
end;
end;
procedure TPixelBuffer.Write(Offset: Integer; const Data: array of Byte);
begin
for each el in Data do
begin
FPixels[Offset] := el;
inc(Offset);
end;
end;
function TPixelBuffer.Read(Offset: Integer; ByteLength: Integer): array of Byte;
begin
result := new Byte[ByteLength];
var xOff := 0;
while ByteLength > 0 do
begin
result[xOff] := FPixels[Offset];
dec(ByteLength);
inc(Offset);
inc(xOff);
end;
end;
procedure TPixelBuffer.Alloc(NewWidth, NewHeight: Integer; const PxFormat: TPixelFormat);
begin
if not GetEmpty() then
Release();
if NewWidth < 1 then
raise new Exception("Invalid width error");
if NewHeight 0 then
result := ( (Result + AlignSize) - xFetch );
end;
end.
This code is just meant to give you a feel for the dialect. I have used a lot of “Delphi style” coding here, so chances are you will hardly see any difference bar namespaces and a funny looking property declaration.
Stay tuned for more posts as I explore the different aspects of Oxygene and webassembly in the days to come 🙂
RemObjects Remoting SDK?
Reading this you could be forgiven for thinking that I must promote RemObjects products, It’s my job now right? Well yes, but also no.
The thing is, I’m really not “traveling salesman” material by any stretch of the imagination. My tolerance for bullshit is ridiculously low, and being practical of nature I loath fancy products that cost a fortune yet deliver nothing but superficial fluff.
The reasons I went to work at RemObjects are many, but most of all it’s because I have been an avid supporter of their products since they launched. I have used and seen their products in action under intense pressure, and I have come to put some faith in their solutions.
Trying to describe what it’s like to write servers that should handle thousands of active user “with or without” RemObjects Remoting SDK is exhausting, because you end up sounding like a fanatic. Having said that, I feel comfortable talking about the products because I speak from experience.
I will try to outline some of the benefits here, but you really should check it out yourself. You can download a trial directly here: https://www.remotingsdk.com/ro/
Remoting framework, what’s that?
RemObjects Remoting framework (or “RemObjects SDK” as it was called earlier) is a framework for writing large-scale RPC (remote procedure call) servers and services. Unlike the typical solutions available for Delphi and C++ builder, including those from Embarcadero I might add, RemObjects framework stands out because it distinguishes between transport, host and message-format – and above all, it’s sheer quality and ease of use.
RemObjects Remoting SDK ships with a rich selection of channels and message formats
This separation between transport, host and message-format makes a lot of sense, because the parameters and data involved in calling a server-method, shouldn’t really be affected by how it got there.
And this is where the fun begins because the framework offers you a great deal of different server types (channels) and you can put together some interesting combinations by just dragging and dropping components.
How about JSON over email? Or XML over pipes?
The whole idea here is that you don’t have to just work with one standard (and pay through the nose for the privilege). You can mix and match from a rich palette of transport mediums and message-formats and instead focus on your job; to deliver a kick-ass product.
And should you need something special that isn’t covered by the existing components, inheriting out your own channel or message classes is likewise a breeze. For example, Andre Mussche have some additional components on GitHub that adds a WebSocket server and client. So there is a lot of room for expanding and building on the foundation provided by RemObjects.
And this is where RemObjects has the biggest edge (imho), namely that their solutions shaves weeks if not months off your development time. And the central aspect of that is their integrated service designer.
Integration into the Delphi IDE
Dropping components on a form is all good and well, but the moment you start coding services that deploy complex data-types (records or structures) the amount of boilerplate code can become overwhelming.
The whole point of a remoting framework is that it should expose your services to the world. Someone working in .net or Java on the other side of the planet should be able to connect, consume and invoke your services. And for that to happen every minute detail of your service has to follow standards.
The RemObjects Service Builder integrates directly into the Delphi IDE
When you install RemObjects SDK, it also integrates into the Delphi IDE. And one of the features it integrates is a complete, separate service designer. The designer can also be used outside of the Delphi IDE, but I cannot underline enough how handy it is to be able to design your services visually, right there and then, in the Delphi IDE.
This designer doesn’t just help you design your service description (RemObjects has their own RODL file-format, which is a bit like a Microsoft WSDL file), the core purpose is to auto-generate all the boilerplate code for you — directly into your Delphi project (!)
So instead of you having to spend a week typing boilerplate code for your killer solution, you get to focus on implementing the actual methods (which is what you are supposed to be doing in the first place).
DLL services, code re-use and multi-tenancy
The idea of multi-tenancy is an interesting one. One that I talked about with regards to Rad-Server both in Oslo and London before christmas. But Rad-Server is not the only system that allows for multi-tenancy. I was doing multi-tenancy with RemObjects SDK some 14 years ago (if not earlier).
Remember how I said the framework distinguishes between transport, message and host? That last bit, namely host, is going to change how you write applications.
When you install the framework, it registers a series of custom project types inside the Delphi IDE. So if you want to create a brand new RemObjects SDK server project, you can just do that via the ordinary File->New->Other menu option.
One of the project types is called a DLL Server. Which literally means you get to isolate a whole service library inside a single DLL file! You can then load in this DLL file and call the functions from other projects. And that is, ultimately, the fundamental principle for multi-tenancy.
And no, you don’t have to compile your project with external packages for this to work. The term “dll-server” can also be a bit confusing, because we are not compiling a network server into a DLL file, we are placing the code for a service into a DLL file. I used this project type to isolate common code, so I wouldn’t have to copy unit-files all over the place when delivering the same functionality.
It’s also a great way to save money. Don’t want to pay for that new upgrade? Happy with the database components you have? Isolate them in a DLL-Server and continue to use the code from your new Delphi edition. I have Delphi XE3 Database components running inside a RemObjects DLL-Server that I use from Delphi XE 10.3.
DLL server is awesome and elegantly solves real-life problems out of the box
In my example I was doing business-logic for our biggest customers. Each of them used the same database, but they way they registered data was different. The company I worked for had bought up these projects (and thus their customers with them), and in order to keep the customers happy we couldn’t force them to re-code their systems to match ours. So we had to come up with a way to upgrade our technology without forcing a change on them.
The first thing I did was to create a “DLL server” that dealt with the database. It exposed methods like openTable(), createInvoice(), getInvoiceById() and so on. All the functions I would need to work with the data without getting my fingers dirty with SQL outside the DLL. So all the nitty gritty of SQL components, queries and whatnot was neatly isolated in that DLL file.
I then created separate DLL-Server projects for each customer, implemented their service interfaces identical to their older API. These DLL’s directly referenced the database library for authentication and doing the actual work.
When integrated with the IDE, you are greeted with a nice welcome window when you start Delphi. Here you can open examples or check out the documentation
Finally, I wrapped it all up in a traditional Windows system service, which contained two different server-channels and the message formats they needed. When the service was started it would simply load in the DLL’s and manually register their services and types with the central channel — and voila, it worked like a charm!
Rock solid
Some 10 years after I delivered the RemObjects based solution outlined above, I got a call from my old employer. They had been victim of a devastating cyber attack. I got a bit anxious as he went on and on about damages and costs, fearing that I had somehow contributed to the situation.
But it turned out he called to congratulate me! Out of all the services in their server-park, mine were the only ones left standing when the dust settled.
The RemObjects payload balancer had correctly dealt with both DDOS and brute force attacks, and the hackers were left wanting at the gates.
New job, new office, new adventures
It’s been roughly 4 weeks since I posted a status report on Amibian.js. I normally keep people up-to-date on facebook (the “Amiga Disrupt” and also “Delphi Developer” groups). It’s been a very hectic month so I fully understand that people are asking. So let’s look at where the project is at and where we are on the time-line.
For those that might not know, I decided to leave Embarcadero a couple of months ago. I will be working out may before I move on. I wanted to write about that myself in a clean fashion, but sadly the news broke on Facebook prematurely.
Long story short, I have been very fortunate to work at Embarcadero. I am not leaving because there is anything wrong or something like that. I was hired as SC for the EMEA regions, which basically made me the support and presenter for most of europe, parts of asia and the middle east. It’s been a great adventure, but ultimately I had to admit that my passion is coding and community work. Sales is a very important part of any company, but it’s not really my cup of tea; my passion has always been research and development.
So, come first of June and I start in a new position at RemObjects. A company that has deep roots with Delphi and C++ builder users – and a company that continues to produce a wealth of high-quality, high-performance frameworks for Delphi and C++ builder. RemObjects also has a strong focus on modern languages, and have a strong portfolio of new and exciting compilers and languages to offer. The Oxygene compiler should be no stranger to Delphi developers, a powerful object-pascal dialect that can target a variety of platforms and chipsets.
Since compiler technology and run-time systems has been my main focus for well over a decade now, I feel RemObjects is a better match.
Quartex Components
Quartex Components has been an officially registered Norwegian company for a while now, so perhaps not news. What is news is that it’s now directly connected with the development of the Quartex Media Desktop (codename “Amibian.js”). While Amibian.js is an open source endeavour, there will be both free and commercial products running on top of that platform. I have written at length about Cloud Forge in the past, so I wont re-hash that again. But 2020 will see a paradigm shift in how teams and companies approach software development.
Company logo professionally milled and on its way to my new office
I will also, once there is more time, continue to sell and support software license components.
Quartex Media Desktop
The “Amibian.js” project is moving along nicely. The deadline is Q4 2019, but im hoping to wrap up the core functionality before that. So we are on track and kicking ass 🙂
More and more elaborate functionality is being implemented for the desktop
Here is an overview of work done this month:
- TSystemService application type has been created (node.js)
- TApplication now holds IPC functions (inter process communication)
- Running child processes + sending messages is now simplicity itself
- Database drivers are 90% done. Delete() and DeleteTable() functionality needs to be implemented in a uniform way
- Authentication is now a separate service
- Service database layer is finished (using SQLite3 driver by default)
- Authentication protocol has been designed
- Server protocol and JSON message envelopes are done
- Presently working on the client interface
- LDEF bytecode assembler has been improved
- Faster symbolic lookup
- Smarter register recognition
- Early support for stack-frames
- Fixed bug in parser (comma-list parse)
- QTX framework has seen a lot of work
- Large parts of the RTL sub-strata has been implemented
- UTF16 codec implemented
- QTX versions of common controls:
- TQTXButton
- TQTXLabel
- TQTXToolbar
- TQTXToolButton
- TQTXToolSeparator
- TQTXToolElement
- TQTXPanel
- TQTXCheckBox
- .. and much, much more
- Desktop changes
- Link Maker functionality has been added
- Handshake process between desktop and child app now runs on a separate timer, ensuring better conformity and a more robust initialization
- The Quartex Editor control has been optimized
- All redraw calls are now synchronized
- Canvas is created on demand, avoids flicker during initial redraw
- Support for DEL key + behavior
- Gutter is now rendered to an offscreen bitmap and blitted into the control’s canvas. The gutter is only fully rendered when cursor forces the view to change
I will continue to keep everyone up to date about the project. As you can understand, its a bit hectic right now so please be patient – it is turning into an EPIC environment!
Understanding a stack
The concept of stacks is an old one, and together with linked-lists and queues – these form the most fundamental programming concepts a developer needs to master.
But, the stack most people use today in languages like object pascal and C++ are not actual stacks; they are more like “conveniently repurposed lists“. Not a huge issue I agree, but the misconception is enough to cause confusion when people dive into low-level programming.
Adventures in assembly-land
It might seem odd to focus on something as trivial as a stack, but I have my reasons. A friend of mine who is a brilliant coder with plenty of large projects behind him recently decided to have a go at assembly coding. He was doing fine and everything was great, until he started pushing and popping things off the stack.
After a little chat I realized that the problem was not his code, but rather how he viewed the stack. He was used to high-level versions of stacks, which in most cases are just lists storing arbitrary sized data – so he was looking at the stack as a TList<item> expecting similar behavior. Superficially a real-stack and a list-stack work the same if all you do is clean push and pop operations, but the moment you start designing a stack-scheme and push more elaborate constructs (stack-frames), things can go wrong really fast.
The nature of a real stack
A “real” stack that is a part of a hardware SOC (system on a chip) has nothing to do with lists. It’s actually a solid chunk of memory with a register to keep track of an offset into this memory block.
Let’s for sake of argument say you have 4k of stack space right? It’s clean and contains nothing, so the SP (stack pointer, or offset) is zero. What happens when you push something to the stack? for example:
push EDX
The code above simply writes the content of the EDX register to whatever offset the SP contains. It then updates the SP with the size of the data (EDX is a 32bit register, so the SP is incremented by a longword or 4 bytes). In Delphi pseudocode what happens is something like:
var LAddr := FStackBuffer; inc(LAddr, SP); PLongword(LAddr)^ := EDX; inc(SP, SizeOf(EDX));
The thing about a stack is that it doesn’t manage data-length for you. And that is a big difference to remember. It will push or pop data based on the size of the source (in this case the 32bit EDX register) you use.
If you push 1024 bytes of data to a list based stack, the list keeps track of the size and data for you. So when you pop the data from the stack, you get back that data regardless. But a “real” stack couldn’t care less — which is also why it’s so easy to screw up an entire program if you make a mistake.
In short: The length of what you push – must be matched when you pop the data back (!) If you push a longword, you MUST pop a longword later.
Benefits of a real stack
The benefit is that the cost of storing values on a stack is almost zero in terms of cpu operations. A list based stack is more expensive; it will allocate memory for a record-item to hold the information about the data, then it will allocate memory to hold the actual data (depends on the type naturally) and finally copy the data into the newly allocated buffer. Hundreds if not thousands of instructions can be involved here.
A real stack will just write whatever you pushed directly into the stack-memory at whatever offset SP is at. Once written it will add the length of the write to the SP – and that’s it! So it’s one of the oldest and fastest mechanisms for lining up data in a predictable way.
Again the rules are simple: when you pop something off the stack, the size must match whatever you used to push it there. So if you pushed a longword (EDX) you also have to make sure you use a 32-bit target when you pop the value back. If you use RDX, which is 64 bit then you will essentially steal 4 bytes from something else using that stack – and all hell will break loose down the line.
Stack schemes and frames
Im not going to dig too deeply into stack-frames here, but instead write a few words about stack-schemes and using the stack to persist data your code relies on. The lines blur between those two topics anyways.
The SP (stack pointer) is not just a simple offset you can read, you can also write and change it (it also serves as a pointer). You can also read from whatever memory the SP is pointing at without polling any data from the stack.
What language developers usually do, is that they design entire structures on the stack that are, when you get into the nitty-gritty, “offset based records”. For example, lets say you have a record that looks like this:
type PMyRecord ) ^TMyRecord; TMyRecord = record first: Pointer; second: integer; Third: array[0..255] of longword; end;
Instead of allocating conventional ram to hold that record, people push it to the stack and then use offsets to read and update the values there. A bit like a super global variable if you like. This is why when you disassemble code, you find stuff like:
mov EDX, (SP)+4
If the above record was on the stack, that pseudo code would move the field “second” into the EDX register. Because that field is 4 bytes from the stack start (providing SP points to zero).
Every programming language has a stack scheme to keep track of things. Local variables, global variables, class instances, type RTTI — most of these things are allocated in conventional ram – but there is a “program record” on the stack that makes it easy to access that information quickly.
This “moving a whole record onto the stack” is basically what a stack-frame is all about. It used to be a very costly affair with a heavy cpu speed penalty. If you look in your Delphi compiler options you will see that there is a checkbox regarding this very topic. Delphi can be told to avoid stack-frames and do register allocation instead, which was super quick compared to stack-frames – but CPU’s today are largely optimized for stack-frame allocation as default, so I doubt there is much to gain by this in 2019.
Note: A stack frame is much more, but its out of scope for this post. Google it for more info.
To sum up
When doing high-level coding you don’t really need to bother with the nuances between a TStack<item> and a “real” stack. But if you plan on digging deeper and learning a few lines of assembly – learning the differences is imperative. Its boring stuff but as fundamental as wheels on a bicycle. There is no way to avoid it, so might as well jump in.
In its absolute raw form, here is roughly the same functionality for Delphi. This was written on the fly in 2 minutes while on the road, so its purely to give you a rough idea of behavior. I would add a secondary field to keep track of the end (next insertion point), that way SP can be changed without overwriting data on new pushes.
And yes, wrapping this in a TObject utterly defeats the purpose of low-level coding, but hopefully it gives you some idea of the differences 🙂
Delphi AST, XML and weekend experiments
One of the benefits of the Delphi IDE is that it’s a very rich eco-system that component writers and technology partners can tap into for their own products. I know that writing your own components is not something everyone enjoy, but knowing that you can in-fact write tools that expands the IDE using just Delphi or C++ builder, opens up for some interesting tools.
Ye old compiler bible
Delphi has a long tradition of “IDE enhancement” software and elaborate third-party tools that automate or delivers some benefit right in the environment. RemObjects SDK is probably the best example of how flexible the IDE truly is. RemObjects SDK integrates a whole service designer, which will generate source-code for you, update the code if you change something – and even generate service manifests for you.
There are also other tools that show off the flexibility of the IDE, ranging from code migration to advanced code refactoring and optimization.
It was with the last bit, namely code refactoring, that a third-party open-source library received a lot of deserving attention a couple of years back. A package called DelphiAST. This is a low-level syntax parser that reads Delphi source-code, applies fundamental syntax checks, and transforms the code into XML. A wet dream for anyone interested in writing advanced tooling that operates directly on source-code level.
Delphi AST
Like mentioned above, DelphiAST is a parser. Its job is very simple: parse the code, perform language level syntax checking, and convert each aspect of the code to a valid XML element. We are not talking about stuffing source-code into a CDATA segment here, but rather breaking each statement into separate tags (begin, end, if, procedure, param) so you can apply filtering, transformations and everything XML has to offer.
Back when Roman first started on DelphiAST, I got thinking — could we follow this idea further, and apply XML transformation to produce something more interesting? Would it actually be possible to approach the notion of compiling from a whole new angle? Perhaps convert between languages in a more effective way?
The short answer is: yes, everything is possible. But as always there are caveats and obstacles to overcome.
First of all, DelphiAST despite its name doesn’t actually generate a fully functional abstract symbol tree (AST). It generates a data model that is very suitable for AST generation, but not an actual AST. Everything in a programming language that can be referenced, like a method, a class, a global variable, a local variable, a parameter – are all called “symbols”. And before you can even think about processing the code, a fast and reliable AST must be in place.
Who cares?
Before I continue, you might be wondering why re-inventing the wheel is even a thing here? Why would anyone research compilers in 2019 when the world is abundant with compilers for a multitude of languages?
Because the world of computing is about to be hit by a tsunami, that’s why.
Quartex Pascal
In the next 8-10 years the world of computing will be turned on its head. NVIDIA and roughly 100 tech companies have invested in open-source CPU designs, making it very clear that playing by Intel’s rules and bleeding royalties will no longer be tolerated. IBM has woken up from its “patent induced slumber” and is set to push their P9 cpu architecture, targeting both the high-end server and embedded market (see my article last year on PPC). At the same time Microsoft and Apple have both signaled that they are moving to ARM (an estimate of 5 years is probably reasonable). Laptop beta’s are said to be already rolling, with a commercial version expected Q3 this year (I think it wont arrive before xmas, but who knows).
Intel has remained somewhat silent about any long-term plans, but everyone that keeps an eye on hardware knows they are working like mad on next-gen FPGA. A tech that has the potential to disrupt the whole industry. Work is also being done to bridge FPGA coding with traditional code; there is no way of predicting the outcome of that though.
Oh and AMD is usurping the Intel marketshare at a steady rate — so we are in for a fight to the death.
The rise of C/C++
Those that keep tabs on languages have no doubt noticed the spike in C/C++ popularity lately. And the cause of this is that developers are safeguarding themselves for the storm to come. C as a language might not be the most beautiful out there, but truth be told, it’s tooling requires the least amount of work to target a new platform. When a new architecture is released, C/C++ is always the first language available. You wont see C#, Flutter or Rust shipping with the latest and greatest; It’s always GCC or Clang.
Note: GCC is not just C, it’s actually a family of languages, so ironically, Gnu Basic hits a platform at the same time.
Those that have followed my blog for the past 10 years, should be more than aware of my experiments. From compiling to Javascript, generating bytecodes – and right now, moving the whole development paradigm to the browser. Hopefully my readers also recognize why this is important.
But to make you understand why I am so passionate about my compiler experiments, let’s do a little thought experiment:
Rethinking tooling
Let’s say we take Delphi, implement a bytecode format and streamline the RTL to be platform agnostic. What would the consequences of that be?
Well, first of all the compiler process would be split in two. The traditional compilation process would still be there, but it would generate bytecodes rather than machine code. That part would be isolated in a completely separate process; a process that, just like with the Delphi IDE’s infrastructure, could be outsourced to component-writers and technology partners. This in turn would provide the community with a high degree of safety, since the community itself could approach new targets without waiting for Embarcadero.
Even more, such an architecture would not be limited to machine-code. There is no law that says “you must convert bytecodes to machine code”. Since C/C++ is the foundation that modern operating-systems rest on, generating C/C++ source-code that can be built by existing compilers is a valid strategy.
There is also another factor to include in all of this, and that is Linux. Borland was correct in their assessment of Linux (the Kylix project), but they failed miserably with regards to timing. They also gravely underestimated Linux user’s sense of quality, depending on Wine (a Windows virtualization framework) to even function. They also underestimated Freepascal and Lazarus, because Linux is something FPC does exceptionally well. Competing financially against free products wont work unless you bring outstanding abilities to the table. And Linux have development tools that rival Visual Studio in quality, yet costs nothing.
But no matter how financially tricky Linux might be, we have reached the point in time where Linux is becoming mainstream. 10 years ago I had to setup my own Linux machine. There were no retailers locally that shipped a Linux box. Today I can walk into two major chains and pick dedicated Linux machines. Ubuntu in particular is well established and delivers LTS.
So for me personally, compiler tech has never been more important. And even more important is the tooling being universal and unbound by any specific API or cpu instruction-set. Firemonkey is absolutely a step in the right direction, but I think it’s a disaster to focus on native UI’s beyond a system level binding. Because replicating the same level of support and functionality for ARM, P9, RISC 5 and whatever monstrosity Intel comes up with through FPGA will take forever.
Transformation based conversion
We have wandered far off topic now, so let’s bring it back to this weekends experiment.
In short, XML transformations to convert code does work, but the right tooling have to be there to make it viable. I implemented a poor-man’s symbol table, just collecting classes, types and methods – and yeah, works just fine. What worries me a bit though is the XML parser. Microsoft has put a lot of money into XML file handling on enterprise level. When working with massive XML files (read: gigabytes) you really can’t be bothered to load the file into conventional ram and then old-school traverse the XML character by character. Microsoft operates with pure memory mapping so that you can process gigabytes like they were megabytes — but sadly, there is nothing similar for Linux, Unix or Android, that abruptly ends the fascination for me.
The only place I see using XML transformations to process source-code, is when converting to another language on source-level.
So the idea, although technically sound, gives zero benefits over the traditional process. I am however very interested in using DelphiAST to analyze and convert Delphi code directly from the IDE. But that will have to be an experiment for 2020, im booked 24/7 with Quartex Media Desktop right now.
But it was great fun playing around with DelphiAST! I loved how clean and neat the codebase has become. So if you need to work with source-code, DelphiAST is just the ticket!
Edit: You dont have to emit the code as XML. DelphiAST is perfectly happy to act as a clean parser, just saying.
