Editing M-expression (section)

{{Short description|Proposed syntax for the Lisp language}}
{{More citations needed|date=August 2013}}
[[File:John McCarthy Stanford.jpg|thumb|100px|John McCarthy]]
In [[computer programming]], '''M-expressions''' (or '''meta-expressions''') were an early proposed syntax for the [[Lisp (programming language)|Lisp programming language]], inspired by contemporary languages such as [[Fortran]] and [[ALGOL]]. The notation was never implemented into the language and, as such, it was never finalized.<ref>{{Cite web|url=http://www-formal.stanford.edu/jmc/history/lisp/node3.html|title=The implementation of LISP|website=www-formal.stanford.edu|access-date=2020-03-29}}</ref>

M-expressions are a syntax for LISP code and provide [[function notation]], syntax for a {{code|cond|lisp}} form and for embedded literal data (via S-expressions) into programs. Thus M-Expressions used S-Expressions for literal data. The syntax for S-Expressions ("The Data Language") and M-Expressions ("The Meta Language") is defined on pages 8 and 9 of the Lisp 1.5 manual.<ref name=LISP15/>

M-Expressions also had a corresponding S-Expression representation.  Code was manually translated from M-Expressions to S-Expressions. The in M-expressions embedded literal data, then had to be quoted in S-Expressions.