Editing Macro (computer science) (section)

==Text-substitution macros==
{{unreferenced section|date=September 2024}}
{{See also|General-purpose macro processor|Assembly language#Macros|Algorithm}}
Languages such as [[C (programming language) |C]] and some [[assembly language]]s have rudimentary macro systems, implemented as [[preprocessor]]s to the compiler or assembler. [[C preprocessor]] macros work by simple textual substitution at the [[Lexical token|token]], rather than the character level. However, the macro facilities of more sophisticated assemblers, e.g., [[IBM High Level Assembler]] (HLASM) can't be implemented with a preprocessor; the code for assembling instructions and data is interspersed with the code for assembling macro invocations.

A classic use of macros is in the computer typesetting system [[TeX]] and its derivatives, where most functionality is based on macros.<ref>{{cite web |last1=Fine |first1=Johnathan |title=T E X forever! |url=http://svn.tug.org/TUGboat/tb27-0/fine.pdf |website=Tex Users Group |access-date=6 December 2024 |page=141 |quote=TEX has a macro programming language, which allows features to be added.}}</ref>

[[MacroML]] is an experimental system that seeks to reconcile [[static typing]] and macro systems. [[Nemerle]] has typed syntax macros, and one productive way to think of these syntax macros is as a [[Metaprogramming|multi-stage computation]].

Other examples:
* [[m4 (computer language)|m4]] is a sophisticated stand-alone macro processor.
* [[TRAC programming language|TRAC]]
* [[METAL|Macro Extension TAL]], accompanying [[Template Attribute Language]]
* SMX: for web pages
* [[ML/I|ML/1]] (Macro Language One)
* [[troff]] and [[nroff]]: for typesetting and formatting Unix manpages.
* [[CMS EXEC]]: for command-line macros and application macros
* [[EXEC 2]] in [[Conversational Monitor System]] (CMS): for command-line macros and application macros
* [[CLIST]] in IBM's [[Time Sharing Option]] (TSO): for command-line macros and application macros
* [[REXX]]: for command-line macros and application macros in, e.g., [[AmigaOS]], CMS, [[OS/2]], TSO
* [[SCRIPT (markup)#SCRIPT macros|SCRIPT]]: for formatting documents
* Various [[Shell (computing)#Text (CLI) shells|shells]] for, e.g., [[Linux]]

Some major applications have been written as text macro invoked by other applications, e.g., by [[XEDIT]] in CMS.

===Embeddable languages===
Some languages, such as [[PHP]], can be embedded in free-format text, or the source code of other languages. The mechanism by which the code fragments are recognised (for instance, being bracketed by <code><?php</code> and <code>?></code>) is similar to a textual macro language, but they are much more powerful, fully featured languages.