Multics Emacs
{{Short description|Multics version of Emacs text editor}}
{{Infobox software
| name = Multics Emacs
| title = Multics Emacs
| logo =
| screenshot = 220px
| caption = Version 12.9, 132 columns
| author = Bernard Greenberg
| developer = Honeywell
| released = {{Start date and age|1978}}
| discontinued =
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| latest release date =
| programming language = Maclisp
| operating system = Multics
| platform =
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| language = English
| language count =
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| genre = Text editor
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}}
Multics Emacs is an early implementation of the Emacs text editor.{{citation
| last = Stallman | first = Richard M.
| contribution = EMACS: the extensible, customizable self-documenting display editor
| doi = 10.1145/800209.806466
| title = Proceedings of the ACM SIGPLAN SIGOA Symposium on Text Manipulation
| year = 1981| hdl = 1721.1/5736
| hdl-access = free
}} It was written in Maclisp by Bernard Greenberg at Honeywell's Cambridge Information Systems Lab in 1978, as a successor to the original 1976 TECO implementation of Emacs and a precursor of later GNU Emacs.{{citation
| last = Finseth | first = Craig A.
| isbn = 9781461231882
| page = 210
| publisher = Springer
| title = The Craft of Text Editing: Emacs for the Modern World
| url = https://books.google.com/books?id=uJHqBwAAQBAJ&pg=PA210
| year = 2012}}
It has been claimed to be the first version of Emacs to be written in the Lisp programming language,{{citation
| last = Seibel | first = Peter
| isbn = 9781430200178
| page = xxi
| publisher = Apress
| title = Practical Common Lisp
| url = https://books.google.com/books?id=dVJvr8PtCMUC&pg=PR20
| year = 2006}} although the same claim has also been made for the Lisp Machine editors EINE and ZWEI, also written in the late 1970s. As well as the editor itself being written in Lisp, user-supplied extensions were also written in Lisp. The choice of Lisp provided more extensibility than ever before, and has been followed by most subsequent Emacs implementations.{{citation
| last = Greenberg | first = Bernard S.
| date = April 8, 1996
| title = Multics Emacs: The History, Design and Implementation
| url = https://www.multicians.org/mepap.html
| work = Multicians}}
Rather than using TECO's gap buffer representation for the text being edited, it used a doubly linked list of lines of text.{{citation
| last1 = Strandh | first1 = Robert
| last2 = Villeneuve | first2 = Matthieu
| last3 = Moore | first3 = Timothy
| contribution = Flexichain: An editable sequence and its gap-buffer implementation
| contribution-url = https://common-lisp.net/project/flexichain/download/StrandhVilleneuveMoore.pdf
| title = Proceedings of the Lisp and Scheme Workshop
| year = 2004}}