Rexx

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Rexx (REstructured eXtended eXecutor) is a high-level computer programming language developed between 1979 and 1982 by M. F. Cowlishaw. Although Cowlishaw, who is an IBM employee, developed the language in his spare time, IBM soon recognized the usefulness of the language and introduced it in 1982 into the operating system VM/CMS as its main scripting language. Around the same time IBM's CMS editor, XEDIT, was extended so that edit macros could be written in Rexx.

At present IBM includes support for the language in almost all its operating systems. Non-IBM freeware versions are available for MS-Windows, most variants of Unix, and Mac OS X.

Features of the language are: easy to learn, procedural, interpreted, untyped (or rather one type: character string of arbitrary length), support of numbers of arbitrary precision, associative arrays, powerful character string parsing, invokable from different environments, passing commands to its invoking environments.

There are text editors, notably IBM's XEDIT[1], Mansfield's KEDIT[2], and Hessling's THE[3], that are integrated with Rexx. This is a powerful combination: from the editor a Rexx macro may be invoked and from the Rexx macro editor statements may be issued. Such a feature allows an almost infinite extension and adaptation of an editor to one's personal needs. To mention just one small example: during an edit session a word under a cursor may be changed cyclically by the aid of a Rexx macro to full uppercase, first letter uppercase, and full lowercase. This function can be assigned to an arbitrary keyboard combination.

References

  1. XEDIT User's Guide. (2d ed., Dec. 2005, pub. no. SC24-6132-01). International Business Machines
  2. KEDIT (commercial)
  3. THE (freeware)

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