This page (revision-270) was last changed on 26-Mar-2023 02:03 by Administrator 

This page was created on 20-Feb-2010 19:16 by Carsten Strotmann

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Version Date Modified Size Author Changes ... Change note
270 26-Mar-2023 02:03 17 KB Administrator to previous
269 26-Mar-2023 02:02 17 KB Administrator to previous | to last
268 26-Mar-2023 02:01 17 KB Administrator to previous | to last
267 26-Mar-2023 02:00 17 KB Administrator to previous | to last ACTION Source Code ==> Action Source Code
266 26-Mar-2023 01:59 17 KB Administrator to previous | to last
265 26-Mar-2023 01:58 17 KB Administrator to previous | to last
264 26-Mar-2023 01:56 17 KB Administrator to previous | to last Remove links to delete manual pages
263 26-Mar-2023 01:22 17 KB Administrator to previous | to last Fix SF links
262 26-Mar-2023 01:21 17 KB Administrator to previous | to last
261 26-Mar-2023 01:18 17 KB Administrator to previous | to last Move manuals to Sourceforge

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!!!ACTION!
!!!Action!
Action! is an Atari-specific programming language written by Clinton Parker and sold by Optimized Systems Software (OSS) in ROM cartridge form starting in August 1983. It is perhaps the only 3rd party language (as opposed to BASIC or assembler) that had real popularity on the platform and saw any significant coverage in the Atari press, with type-in programs and various technical articles found in most magazines at one time or another. In comparison, other languages like [Forth] and [Logo] saw much less use and almost no press coverage.
Action! uses a greatly cut-down version of the ALGOL68 syntax, and thus bears strong similarities with Pascal and C. Like those languages, Action! is procedural, with programs essentially being a large collection of functions that call each other. It lacked encapsulation or data hiding, but that is not a serious concern in the limited program size available on an 8-bit machine. Syntactically it looks very similar to Pascal, with the exception that it uses DO/OD style braketting rather than Pascal's BEGIN/END.
Action! included a number of features specifically intended to make it run as fast as possible. Notably, it's main data types were BYTE, INT and CARD, 8-bit and 16-bit signed and unsigned values, respectively. These map directly onto the basic 6502-types, and the language also included a simple syntax to directly refer to these objects in memory so they could be mapped into hardware registers. For instance, one could set a variable to "BYTE RTCLOK=20" which defined the 8-bit value at hex 20 to be the value of the real-time clock. The user could then read that register using the name "RTCLOK".
Curiously, Action! did not include support for floating point types, although such support is built into the machine's OS ROM (see Atari BASIC for details) and available to any programming language. This is a significant limitation in some roles, although perhaps not for its target market. It also lacked most string handling, but made up for this somewhat with a PRINTF command that made formatted output easy.
''Editor's note: A version of Action! with support for a FLOAT type and a replacement floating point library like the ones in Fastchip or Turbo-Basic would be a very interesting project.''
Generally, Action! programs had performance on-par with reasonable-quality assembler, while being much easier to program. In one review, it ran Byte's Sieve of Eratosthenes 219 times faster than Atari BASIC, while being only slightly longer than BASIC in source form, about a page, compared to several pages of assembler. Such performance, combined with terse code and library functions to access much of the platform's hardware, made it suitable for action games while still having a simple format suitable for type-in programs. It deserved to be much more popular and may have been had it been released earlier, or by Atari itself.
Action! inspired several similar languages that differ largely in syntax and various features that they do or do not support. Examples include [PL65] and [Quick].
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