ARexx
ARexx is an implementation of the
ARexx can easily communicate with third-party software that implements an "ARexx port". Any Amiga application or script
ARexx can direct commands and functions to several applications from the same script, thus offering the opportunity to mix and match functions from the different programs. For example, an ARexx script could extract data from a database, insert the data into a spreadsheet to perform calculations on it, then insert tables and charts based on the results into a word processor document.
History
ARexx was first created in 1987, developed for the Amiga by William S. Hawes. It is based on the REXX language described by
ARexx is written in
From the ARexx manual:
ARexx was developed on an Amiga 1000 computer with 512k bytes of
memory and two floppy disk drives. The language prototype was
developed in C using Lattice C, and the production version was written
in assembly-language using theMetacomcoassembler. The documentation
was created using the TxEd[3] editor, and was set in TeX using AmigaTeX.
This is a 100% Amiga product.[4]
Characteristics
ARexx is a programming language that can communicate with other applications. Using ARexx, for example, one could request data from a database application and send it to a spreadsheet application. To support this facility, an application must be "ARexx compatible" by being able to receive commands from ARexx and execute them. A
ARexx can increase the power of a computer by combining the capabilities of various programs. Because of the popularity of a stand-alone ARexx package, Commodore included it with Release 2 of AmigaDOS.
Like all REXX implementations, ARexx uses typeless data representation. Other programming languages made distinctions between
ARexx scripts benefit from an
The ARexx command set is simple, but in addition to the commands there are the functions of its Amiga reference library (rexxsyslib.library). It is also easy to add other libraries or individual functions. ARexx scripts can also be invoked as functions from other ARexx scripts. Any Amiga program which has an ARexx port built in can share its functions with ARexx scripts.
Examples of ARexx solutions to common problems
Implementing new features and capabilities via scripts
If end user is using a program which builds animations by joining various
- ARexx locates the image files in their directories
- ARexx loads first image
- ARexx loads paint program
- The image is loaded into paint program which performs modifications to file
- The modified image is stored into another directory
- ARexx repeats procedure on any image in the directory
- The paint program is closed and the animation program is loaded
- The animation is built
- The animation is saved in its directory
- The animation program is closed
Avoiding repetitive procedures
EqFiles.rexx[5] is a well-known example of a simple ARexx script written to automate repetitive and boring procedures. This script uses the ALeXcompare program [6] to compare files, and then finds all duplicates in a set of files and returns output by highlighting any results in a different color.
Expand AmigaOS capabilities
One of the main features of ARexx is the fact it could expand the capabilities of the AmigaOS by adding some procedures the OS lacked. For example, a simple ARexx program could be written to print a warning message on the screen of the monitor, or play an audio alert signal if a certain Amiga program stops, faults or has finished its scheduled job.
The following script is a minimal ARexx script that displays warnings depending on events that take place.
/* Alarm.rexx */
ARG event
IF event = 0 THEN EXIT
IF event = 1 THEN SAY "Program has ended unexpectedly"
IF event = 2 THEN SAY "Program has finished its job"
IF event = 3 THEN SAY "Cannot find data in selected directory"
See also
- REXX
References
- ^ Giguere, Eric. "ARexx Command Hosts".
- ISBN 0-13-780651-5.
- ^ "Amazing_Computing_1986-03_067.JPG".
- ^ ARexx Users Reference Manual
- ^ Peruggi, Fulvio. "EqFiles".
- ^ Kazik, Alex. "ALeXcompare".
- Notes
- Callaway, Merrill. (1992). The ARexx cookbook. Albuquerque, NM: Whitestone. ISBN 0-9632773-0-8.
- Zamara, Chris; Sullivan, Nick (1991). Using Arexx on the Amiga. Abacus Software Inc. ISBN 1-55755-114-6.