Editing M-expression (section)

== Implementations ==

=== For LISP ===

[[MLisp]] was a contemporary (1968–1973) project to implement an M-expression-like frontend for Lisp. A few extra features like [[hygienic macro]]s, [[pattern matching]], and [[backtracking]] were incorporated. It eventually evolved into an abandoned [[LISP70]] draft. M-LISP ([[MetaLISP]]) from 1989 was another attempt to blend M-expressions with Scheme.<ref name="xl"/>

A parser for the "[[AI Memo]] 8" M-expression is available in [[Common Lisp]], but the author intends it as a case against M-expressions due to its perceived inability to cope with macros.<ref>{{cite web |title=A Parser for M-Expressions |url=https://www.informatimago.com/develop/lisp/com/informatimago/small-cl-pgms/m-expression/ |url-status=dead |archive-url=https://web.archive.org/web/20210324084457/https://www.informatimago.com/develop/lisp/com/informatimago/small-cl-pgms/m-expression/ |archive-date=24 March 2021 |quote=Let's newbies play with them, and realize how impractical they are. Note for example, that we cannot use macros anymore because their syntax would need to be known by the M-expression parser.}}</ref>