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Delphi programming language

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Delphi is the primary programming language of Borland Delphi. The Delphi language is a derivative of Borland's Object Pascal, which is itself a derivative of Pascal.

The Delphi programming language was created by Borland and debuted with the first version of Borland Delphi. Borland sells integrated development environments (IDEs) that compile the Delphi programming language to Microsoft Windows, the Microsoft .NET Framework and Linux. The open source Free Pascal project allows the language to be compiled for Mac OS X, Win64 and Windows CE.

Programming language and toolkit

The main distinguishing features of Delphi and Kylix from other IDEs are the Delphi language, the VCL/CLX (Visual Component Library), strong emphasis on database connectivity, and a large number of third party components.

  • delegation of interface implementation to a field or property of the class
  • implementation of message handlers by tagging a method of a class with the integer constant of the message to handle
  • COM independent interfaces with reference counted class implementations
  • can be compiled into native x86 code or managed .NET code

Pros and cons

Delphi exhibits the following advantages:

  • Rapid Application Development (RAD)
  • based on a well-designed language
  • a large community on Usenet and the web (e.g. news://forums.borland.com and Borland's web access to Delphi newsgroups)
  • can compile to a single executable, simplifying distribution and reducing dll versioning issues
  • many VCL and third-party components (usually available with full source code) and tools (documentation, debug tools, etc.)
  • quick optimizing compiler and ability to use assembler code
  • multiple platform native code from the same source code
  • high level of source compatibility between versions
  • CrossKylix - a third-party toolkit which allows you to compile native Kylix/Linux applications from inside the Windows Delphi IDE, hence easily enabling dual-platform development and deployment
  • CrossFPC - a sister project to CrossKylix, which enables you to cross-compile your Windows Delphi applications to multi-platform targets - supported by the Free Pascal compiler - without ever leaving the Delphi IDE
  • class helpers to bridge functionality available natively in the Delphi RTL, but not available in a new platform supported by Delphi

The following are disadvantages:

  • the language's object orientation features only class and interface-based polymorphism
  • partial single vendor lock-in (Borland alone can set the language standard, the compatibles have to follow)
  • limited cross-platform capability for Delphi itself. Compatibles provide more architecture/OS combinations
  • access to platform and third party libraries require header files to be translated to Pascal
  • documentation of platforms and techniques hard to find in Pascal language (e.g., access to COM and WIN32, when compared to VB/MSVC)

Trivia

Clones and alternatives

While not being a direct substitute for the entire product Delphi itself, there are a number of efforts that strive to be more or less language compatible and take Delphi code to places where Delphi and Kylix itself can not reach.

These can get Delphi code running in ways not possible with Delphi (such as supporting different operating systems, free distribution and educational use, and allowing examination of the compiler source) and allow for some vendor independence. These are generally used educationally and to get the server parts of Delphi apps running on non-mainstream operating systems; most had Linux support years before Kylix.

  • Bloodshed Dev-Pascal A very polished graphical 32-bit Windows editor (though not RAD) as a frontend for both GNU Pascal and Free Pascal.
  • Free Pascal A commandline compiler that aims source compatibility with the core feature set of both the Turbo Pascal and Delphi dialects. The current version is 2.0(.2), which are highly Delphi6/7 compatible. Operates on most x86 operating systems. Supports Linux, Mac OS and Mac OS X (including an Xcode implementation) on PowerPC family, and Linux on AMD64. SPARC and Acorn RISC Machine (ARM) architectures are working and formally released but not 100% end-user ready yet.
    • Lazarus [1] is an effort to build a RAD on top of Free Pascal. The internal classes hierarchy can base itself on several graphical toolkits. The main toolkits are GTK1 and Win32, and GTK2 and Windows CE have already come a long way. Qt is also partially supported. Occasionally people want .NET and wxWidgets, but an apparent lack of interest prevents the implementation of these toolkits.
    • CrossFPC - a free toolkit to integrate the Free Pascal compiler, targeting various OS and hardware platforms, into the Windows Delphi IDE. See more about it from this mailing list discussion.
  • GNU Pascal (Separately distributed part of the GNU Compiler Collection) While formally not aimed at the Borland dialects of Pascal, it does contain a Borland Pascal compatibility mode, and is very slowly absorbing Delphi language features, though not yet directly suitable for recompiling large bodies of Delphi code. It is the most prolific compiler in terms of operating systems and processors though, and therefore deserves mentioning as a last resort.
  • InnerFuse is a Delphi interpreter for embedding in applications. It is rumoured to work with several of the alternatives too.
  • OpenSibyl is another effort to build a RAD on top of Free Pascal. However it is geared towards OS/2, and still in initial stages.
  • Vector Pascal Vector Pascal is a language targeted at SIMD instruction sets such as the MMX and the AMD 3d Now, supporting all Intel and AMD processors, as well as the Sony Playstation 2 Emotion Engine.
  • Virtual Pascal is a x86 32-bit Turbo Pascal and Delphi compatible compiler mainly aimed at OS/2 and Windows, though it developed a DOS+Extender and an experimental Linux cross-compiler too. The compiler is stuck on the level of about Delphi V2, and the site hasn't changed significantly in two years, and development of Virtual Pascal has stopped. Nevertheless, of the free alternatives, it is still the one with the best polished IDE and debugger though Free Pascal is getting nearer and nearer.
  • WDOSX is a Win32 API-emulating DOS extender that can be used to get Delphi console applications running on plain DOS.
  • Winsoft Pocket Studio aims to compile stripped down Delphi code to PDAs.
  • Game Maker for Windows also uses a Delphi-based programming language, in the form of GML (Game Maker Language).special:cite

Documentation

Delphi Developer documentation from Borland:

More from Delphi Developer Support section (FTP archives).

See also

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