macro

A name (possibly followed by a formal argument list) that is

equated to a text or symbolic expression to which it is to be

expanded (possibly with the substitution of actualarguments) by a macro expander.

The term "macro" originated in early assemblers, which

encouraged the use of macros as a structuring and

information-hiding device. During the early 1970s, macro

assemblers became ubiquitous, and sometimes quite as powerful

and expensive as HLLs, only to fall from favour as improving

compiler technology marginalised assembly language

programming (see languages of choice). Nowadays the term is

most often used in connection with the C preprocessor,

Lisp, or one of several special-purpose languages built

around a macro-expansion facility (such as TeX or Unix's

troff suite).

Indeed, the meaning has drifted enough that the collective

"macros" is now sometimes used for code in any special-purpose

application control language (whether or not the language is

actually translated by text expansion), and for macro-like

entities such as the "keyboard macros" supported in some text

editors (and PC TSRs or Macintosh INIT/CDEV keyboard

enhancers).

(1994-12-06)