AmigaBASIC - History and Description

History and Description

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, system and file utilities and desk accessories such as 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.

AmigaBASIC itself was rendered obsolete because of incompatibilities with AmigaOS 2.0 and the hardware successors to the Motorola 68000 CPU. Some incompatibilities were due to the disregard of 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, they 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Although AmigaBASIC was superseded by ARexx in AmigaOS 2.0, the two languages had very different functions and capabilities.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.

AmigaBASIC was the first BASIC interpreter not to use line numbering method, and adopting instead of it a more practical direct top-down approach of executing the instructions, and labels to indicate the GOTO instruction where to jump. It was also the first Microsoft interpreted language capable of calling OS functions and dynamic libraries through the command "LIBRARY". For example: LIBRARY Graphics.library command invokes the standard Amiga Graphics.library from which to call functions.