Map (higher-order function): Difference between revisions

Revision as of 00:24, 29 January 2016

Revision as of 07:24, 29 January 2016

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The map function originated in [[functional programming]] languages.

The [[Lisp (programming language)|Lisp programming language]] introduced a map function called <code>maplist</code><ref>[http://www.softwarepreservation.org/projects/LISP/MIT/LISP_Prog_Man-Mar_1959.pdf/view J. McCarthy, K. Maling, S. Russell, N. Rochester, S. Goldberg, J. Slagle. LISP Programmer's Manual. March-April, 1959]</ref> in 1959, with slightly different versions already appearing in 1958.<ref>[http://www.softwarepreservation.org/projects/LISP/MIT/AIM-004.pdf/view J. McCarthy: Symbol Manipulating Language - Revisions of the Language. AI Memo No. 4, October 1958]</ref>. This is the original definition for <code>maplist</code>, mapping a function over successive rest lists:

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The function <code>maplist</code> is still available in newer Lisps like [[Common Lisp]],<ref>[http://www.lispworks.com/documentation/HyperSpec/Body/f_mapc_.htm Function MAPC, MAPCAR, MAPCAN, MAPL, MAPLIST, MAPCON in ANSI Common Lisp]</ref>, though functions like <code>mapcar</code> or the more generic <code>map</code> would be preferred.

Squaring the elements of a list using <code>maplist</code> would be written in s-expression notation like this: