Object Pascal

In 1986, Borland introduced similar extensions, also named Object Pascal, to the Turbo Pascal product for the Macintosh, and in 1989 for Turbo Pascal 5.5 for DOS. When Borland refocused from DOS to Windows in 1994, they created a successor to Turbo Pascal, named Delphi, and introduced a new set of extensions to create what is now known as the Delphi language.

The development of Delphi started in 1993 and Delphi 1.0 was officially released in the United States on 14 February 1995. While code using the Turbo Pascal object model could still be compiled, Delphi featured a new syntax using the keyword class in preference to object, the Create constructor and a virtual Destroy destructor (and negating having to call the New and Dispose procedures), properties, method pointers, and some other things. These were inspired by the ISO working draft for object-oriented extensions, but many of the differences from Turbo Pascal's dialect (such as the draft's requirement that all methods be virtual) were ignored.

The Delphi language has continued to evolve over the years to support constructs such as dynamic arrays, generics and anonymous methods. The old object syntax introduced by Apple ("Old-Style Object Types") is still supported.[6]

• Borland used the name Object Pascal for the programming language in the first versions, but later renamed it to Delphi. Compilers that claim to be compatible with Object Pascal are often trying to be compatible with Delphi source code. Because Delphi is a trademark, compatible compilers continue using the name Object Pascal.
• Embarcadero Technologies, which purchased Delphi in 2008,[7] sells the Delphi integrated development environment (IDE) that compiles the Delphi dialect of Object Pascal to Windows and macOS, iOS, Android and Web.
• .NET support existed from Delphi 8 through Delphi 2005, 2006, and 2007, which now has been replaced by another language, Oxygene (see below), which is not fully backward-compatible.
• The Oxygene language developed by RemObjects Software targets the Common Language Infrastructure, the Java Runtime Environment and Apple's Cocoa frameworks for iOS and macOS.
• The open source Free Pascal project allows the language to be compiled for a wide range of operating systems, including Linux (32-bit, 64-bit), FreeBSD, Classic Mac OS, macOS, Solaris, Windows API (32, 64, CE), the ARM instruction set architecture (ISA), and several other hardware architectures. The first version of Free Pascal for the iPhone software development kit (SDK) 2.x was announced on January 17, 2009.[8]
• The Smart Pascal language[9] targets ECMAScript–JavaScript and is used in Smart Mobile Studio, written by Jon Lennart Aasenden and published by Optimale Systemer (2012). The language greatly simplifies HTML5 development through object-oriented, and rapid application development (RAD) methods. Smart Pascal integrates tightly with established technologies such as node.js, Embarcadero DataSnap, and Remobjects SDK to produce high-performance client–server model web applications. The language allows easy creation of visual components and reusable libraries. The Smart Pascal dialect stems from the DWScript language, extended to better integrate with the JavaScript environment and libraries, such as asm sections which are plain JavaScript but have access to Pascal symbols, or external classes which map directly to prototypal JavaScript classes. Smart Pascal introduces true inheritance, classes, partial classes, interfaces, a virtual method table and many other advanced constructs which are not a part of JavaScript by default.
• MIDletPascal runs on a Java virtual machine (JVM) bytecode platform; which Free Pascal also targets, with far more features.
• The Morfik Pascal language, developed by Morfik, targets Ajax-enabled Web applications. The compiler is built into the company's AppsBuilder IDE and allows Object Pascal code to be used in implementing code to execute in a browser or server. It uses the Free Pascal compiler to generate native binaries from Object Pascal.
• The open source GNU Pascal compiler is available as a front-end to the GNU Compiler Collection, which implements the International Organization for Standardization (ISO) 7185 Pascal standard, and most of the ISO 10206 Extended Pascal standard.
• Turbo51 is a free compiler to program Intel 8051 chips.[10]
• WDSibyl is an open source Delphi-like IDE and compiler available for Microsoft Windows and OS/2,[11] and is a commercial Turbo Pascal compatible environment released by a company named Speedsoft that was later developed into a Delphi-like RAD environment named Sybil, and then open sourced under the GPL when that company closed down. Wolfgang Draxler (WD) now maintains the software. The compiler used seems to be located in a DLL and is not open-source.

Object Pascal compilers are available for a wide range of operating systems and architectures.

• Delphi is probably the best known compiler. It is the successor of the highly successful Borland Pascal and Turbo Pascal product line. It targets Windows 9x (Delphi 2007 and older), the Windows NT family, .NET Framework (Delphi 8, 2005, 2007), macOS (Delphi XE2 and later), iOS (Delphi XE2 and later, generating native binaries in XE4 and later), Android (Delphi XE5 and later, generating native binaries in XE5 and later). Support for .NET finally became a separate product known as Oxygene (see below).
• Free Pascal Compiler (FPC) is an open-source Object Pascal compiler that supports many Pascal dialects, including Turbo Pascal 7, Delphi, and others. Currently, FPC can generate code for IA-32, x86-64, PowerPC, SPARC, and ARM processors, and for several operating systems, including Microsoft Windows, Linux, FreeBSD, Classic Mac OS, and macOS (with an Xcode integration kit). Several separate projects exist to facilitate rapid application development with FPC, the most prominent one being Lazarus (IDE).
• GNU Pascal (a separately distributed part of the GNU Compiler Collection), while not formally aimed at the Delphi dialect of Pascal, does contain a Turbo Pascal compatibility mode, and is very slowly incorporating a few Delphi language features. It is unsuitable for recompiling large bodies of Delphi code directly, but is notable as having prolific support for operating systems and hardware architectures.
• Oxygene (formerly Chrome) is an Object Pascal compiler from RemObjects Software that integrates into Microsoft Visual Studio. It is also available as free command-line interface compiler that runs native on CLI. It is three compilers in one, each targeting a different platform: Echoes for .NET Framework, Mono, WinRT and Windows Phone 8, Cooper for JDK and Android, and Nougat for iOS and macOS.
• MIDletPascal is a mobile application development tool that generates Java ME bytecode.
• PocketStudio is a Pascal-based integrated development environment (IDE) for Palm OS.
• Smart Mobile Studio is a source-to-source compiler that transforms Pascal source code to JavaScript
• Ultibo.org Core is based on Free Pascal, with development in the Lazarus IDE for embedded Raspberry Pi applications.

Pascal Script (formerly InnerFuse) and DWScript (Delphi Web Script) are open-source Object Pascal interpreters and scripting engines written in Delphi. They support subsets of Object Pascal. DWScript can also compile Object Pascal code into JavaScript code (Smart Pascal), and supports just-in-time compilation (JIT). Modern Pascal provides 3 different interpreters: a command-line interface (CLI), Apache Module (Celerity), and CodeRunner (node.js like solution able to handle different scripts per port), besides the ability to compile and protect a script's source code.[12]

Here are several "Hello World" programs in different Object Pascal versions.

program ObjectPascalExample;

   type
      THelloWorld = object
         procedure Put;
      end;

   var
      HelloWorld: THelloWorld;

   procedure THelloWorld.Put;
   begin
      ShowMessage('Hello, World!');
   end;

begin
   New(HelloWorld);
   HelloWorld.Put;
   Dispose(HelloWorld);
end.

program ObjectPascalExample;

   type
      THelloWorld = object
         procedure Put;
      end;

   procedure THelloWorld.Put;
   begin
      WriteLn('Hello, World!');
   end;

var
  HelloWorld: THelloWorld; { allocated on the stack and can be used without explicit allocation. }
begin
   HelloWorld.Put;
end.

program ObjectPascalExample;

   type
      PHelloWorld = ^THelloWorld;
      THelloWorld = object
         procedure Put;
      end;

   procedure THelloWorld.Put;
   begin
      WriteLn('Hello, World!');
   end;

var
  HelloWorld: PHelloWorld; { this is a typed pointer to a THelloWorld }

begin
   New(HelloWorld);
   HelloWorld^.Put;
   Dispose(HelloWorld);
end.

program ObjectPascalExample;

   type
      PHelloWorld = ^THelloWorld;
      THelloWorld = object
         procedure Put;
      end;

   procedure THelloWorld.Put;
   begin
      WriteLn('Hello, World!');
   end;

var
  HelloWorld: PHelloWorld; { this is a typed pointer to a THelloWorld }
  HelloWorld2: ^THelloWorld; { this is exactly the same with different syntax } 
  HelloWorld3: ^THelloWorld;                               
  HelloWorld4: PHelloWorld;   
begin
   { This works in a similar way as the code above, note the allocation and de-allocation, though,
     many people get confused. In the past there was a wrong example with wrong comments here... }

   New(HelloWorld);  { one instance }
   HelloWorld4 := HelloWorld; { this is valid - a pointer copy }
   HelloWorld2 := HelloWorld; { this is valid - a pointer copy }
   New(HelloWorld3); { a second instance }
   HelloWorld4 := HelloWorld3; { this is valid - a pointer copy }
   HelloWorld2 := HelloWorld3; { this is valid - a pointer copy }
   Dispose(HelloWorld);  { it allocates only two instances }
   Dispose(HelloWorld3); { so it must release only two instances }
end.

program ObjectPascalExample;

type
  THelloWorld = class
    procedure Put;
  end;

procedure THelloWorld.Put;
begin
  Writeln('Hello, World!');
end;

var
  HelloWorld: THelloWorld;               { this is an implicit pointer }

begin
  HelloWorld := THelloWorld.Create;      { constructor returns a pointer to an object of type THelloWorld }
  HelloWorld.Put;
  HelloWorld.Free;                       { this line deallocates the THelloWorld object pointed to by HelloWorld }
end.

namespace ObjectPascalExample;

   interface

   type
      ConsoleApp = class
         class method Main;
      end;

      THelloWorld = class
         method Put;
      end;

   implementation

   method THelloWorld.Put;
   begin
      Console.WriteLine('Hello, World!');
   end;

   class method ConsoleApp.Main;
   begin
      var HelloWorld := new THelloWorld;
      HelloWorld.Put;
   end;

end.

type
   THelloWorld = class
      procedure Put;
      begin
         PrintLn('Hello, World!');
      end
   end;

var HelloWorld := THelloWorld.Create;
HelloWorld.Put;

Many features have been introduced continuously to Object Pascal with extensions to Delphi and extensions to FreePascal. In reaction to criticism, Free Pascal has adopted generics with the same syntax as Delphi, provided Delphi compatibility mode is selected, and both Delphi (partial) and Free Pascal (more extensive) support operator overloading. Delphi has also introduced many other features since version 7,[13] including generics. Whereas FreePascal tries to be compatible to Delphi in Delphi compatibility mode, it also usually introduced many new features to the language that are not always available in Delphi.

• Introduction to Object Pascal, MacTech Vol 2 Issue 12 1985.
• Object Pascal reference guide for Free Pascal. Archived 2009-12-23 at the Wayback Machine "The aim is to list which Pascal constructs are supported, and to show where the Free Pascal implementation differs from the Turbo Pascal or Delphi implementations."
  • Free Pascal: Reference guide, Reference guide for Free Pascal, version 2.0.0
• Major Differences Between the Syntax of C++ and Object Pascal
• Think Pascal 4.5 Unofficial page about Symantec's final version of Think Pascal.