AmigaBASIC

File:AmigaBASIC.png

AmigaBASIC running the "Demo" program

AmigaBASIC was an interpreted BASIC programming language implementation for the Amiga, designed and written by Microsoft. AmigaBASIC shipped with AmigaOS versions 1.1 to 1.3. It succeeded Metacomco's ABasiC, which was included in AmigaOS 1.0 and 1.1, and it was replaced with ARexx, a REXX-style scripting language, from AmigaOS version 2.0 onwards.

AmigaBASIC provided not only the common BASIC language, but also attempted to provide an easy-to-use API for the Amiga's unique graphics and sound capabilities. OBJECT commands, for example, made it easy to create moving objects - sprites and bobs that could be drawn with an external drawing program, Object editor, that was supplied with AmigaBASIC. An unusual feature of the language is that it theoretically allowed the calling of handwritten assembly language subprograms; however, this feature never worked because of a bug that failed to align the assembly language instructions correctly on a word boundary, as required by the Amiga's native MC68000 processor.

Compute!, a popular computer magazine published while AmigaBASIC was still being shipped, included many AmigaBASIC programs in their articles. Compute! readers could type the source code into the AmigaBASIC editor to add new software to their Amiga. The source code listings were typically implementations of simple programs, such as rudimentary games, analog clocks and address books.

Many of today's successful computer programmers got their start on AmigaBASIC, including a few that work at Valve Software, the company that makes the Half-Life series of games.^{[citation needed]}

AmigaBASIC itself was rendered obsolete by being incompatible with AmigaOS 2.0 and also hardware based on successors to the Motorola 68000 CPU due to its neglect of some programming guidelines set forth by Commodore. However, there were a number of third-party compiled BASIC languages released for the Amiga that could compile AmigaBASIC programs with minimal changes, like A/C BASIC or Cursor (see below). Some of these compiled BASICs continued to work with AmigaOS 2.0, and as they were compiled rather than interpreted, generally ran much faster than the original.

Although AmigaBASIC was superseded by ARexx in AmigaOS 2.0, the two languages had very different functions and capabilities. Hobbyist programmers had changed by the time of this release and were more likely to be interested in incorporating existing third party applications into their programs than in writing new programs entirely from scratch. ARexx was seen as better fitting their needs than the older BASIC interpreter.

Hello World in AmigaBASIC

' Hello World for AmigaBASIC
PRINT "Hello, world!"

You can go one better by adding the following line:

SAY TRANSLATE$ ("HELLO WORLD")

The Amiga will then actually say "Hello, world." in addition to displaying it on screen.

Other BASIC languages for AmigaOS

• Metacomco ABasiC was a non-Microsoft Basic that was shipped with Amiga 1000 systems with Workbench 1.0, before AmigaBasic was available. ABasiC provided a more traditional Basic programming environment, requiring numbered lines and lacking support for Intuition windowing. ABasiC did provide very good support for Amiga graphics and sound features otherwise, however.
• ACE was an AmigaBASIC compiler, written by David Benn. The compiler produced Motorola 68000 assembly language which could be assembled and linked into native Amiga executables. The primary benefits were performance, lower run-time memory requirements, the ability to execute software without AmigaBASIC, and the ability to distribute software without having to release the actual source code. ACE also provided additional language constructs to expand upon the capability of the AmigaBASIC language.
• A/C Basic by Absoft was a compiler for AmigaBASIC programs that turned them into native executables that could be run without AmigaBASIC or the program's source code being present.
• Cursor was another AmigaBASIC editor and compiler.
• GFA BASIC, originally developed for the Atari ST, was ported to the Amiga platform by its author, Frank Ostrowski.
• HiSoft BASIC was another BASIC variant ported from the Atari ST to the Amiga.
• AMOS BASIC, developed by François Lionet, was a commercial language which provided extensive support for the Amiga's graphics hardware and was designed primarily for games programming. It was used to write several commercial games and educational software.
• Blitz BASIC was a direct commercial competitor to AMOS, published by Acid Software. Like AMOS, it was targeted at games programming. Its successor, Blitz Basic 2, was used to write several commercial games, including the popular Team17 game Worms.

Example AmigaBASIC code

• COMPUTE!, August 1987, pg 89 Fractal Mountains For Amiga – Source code listing of a fractal mountain generator.
• COMPUTE!, October 1987, pg 71 A Button Command – Source code listing for enhanced buttons, such as radio-style buttons.
• COMPUTE!, November 1987, pg 86 Masked Input For The Amiga – Source code listing for a masked text input box.