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Emacs and its derivatives are a family of text editors that are characterized by their extensibility. The manual for the most widely used variant, GNU Emacs, describes it as "the extensible, customizable, self-documenting, real-time display editor". Development of the first Emacs began in the mid-1970s and continues actively . Emacs has over 2,000 built-in commands and allows the user to combine these commands into macros to automate work. Emacs Lisp provides a deep extension capability allowing users and developers to write new commands using a dialect of the Lisp programming language. The original EMACS was written in 1976 by Richard Stallman and Guy L. Steele, Jr. as a set of ''Editor MACroS'' for the TECO editor.〔(【引用サイトリンク】 Multics Emacs: The History, Design and Implementation )〕〔(【引用サイトリンク】 Emacs Timeline )〕〔(【引用サイトリンク】 MACSimizing TECO )〕 It was inspired by the ideas of the TECO-macro editors TECMAC and TMACS. The most popular, and most ported, version of Emacs is GNU Emacs, which was created by Stallman for the GNU Project. XEmacs is a variant that branched from GNU Emacs in 1991. Both GNU Emacs and XEmacs use Emacs Lisp and are for the most part compatible with each other. Emacs is, along with vi, one of the two main contenders in the traditional editor wars of Unix culture. Both are among the oldest application programs still in use. == History == Emacs development began during the 1970s at the MIT AI Lab, whose PDP-6 and PDP-10 computers used the Incompatible Timesharing System (ITS) operating system that featured a default line editor known as Tape Editor and Corrector (TECO). Unlike most modern text editors, TECO used separate modes in which the user would either add text, edit existing text, or display the document. One could not place characters directly into a document by typing them into TECO, but would instead enter a character ('i') in the TECO command language telling it to switch to input mode, enter the required characters, during which time the edited text was not displayed on the screen, and finally enter a character ( Richard Stallman visited the Stanford AI Lab in 1972 or 1974 and saw the lab's ''E'' editor, written by Fred Wright. He was impressed by the editor's intuitive WYSIWYG (What You See Is What You Get) behavior, which has since become the default behavior of most modern text editors. He returned to MIT where Carl Mikkelsen, a hacker at the AI Lab, had added to TECO a combined display/editing mode called ''Control-R'' that allowed the screen display to be updated each time the user entered a keystroke. Stallman reimplemented this mode to run efficiently and then added a macro feature to the TECO display-editing mode that allowed the user to redefine any keystroke to run a TECO program.〔 E had another feature that TECO lacked: random-access editing. TECO was a page-sequential editor that was designed for editing paper tape on the PDP-1 and typically allowed editing on only one page at a time, in the order of the pages in the file. Instead of adopting E's approach of structuring the file for page-random access on disk, Stallman modified TECO to handle large buffers more efficiently and changed its file-management method to read, edit, and write the entire file as a single buffer. Almost all modern editors use this approach. The new version of TECO quickly became popular at the AI Lab and soon accumulated a large collection of custom macros whose names often ended in ''MAC'' or ''MACS'', which stood for ''macro''. Two years later, Guy Steele took on the project of unifying the overly diverse macros into a single set.〔(【引用サイトリンク】title=EMACS vs. vi: The endless geek 'holy war' )〕 Steele and Stallman's finished implementation included facilities for extending and documenting the new macro set.〔 The resulting system was called EMACS, which stood for ''Editing MACroS'' or, alternatively, ''E with MACroS''. Stallman picked the name Emacs "because Stallman saw a problem in too much customization and ''de facto'' forking and set certain conditions for usage. He later wrote:〔 :''"EMACS was distributed on a basis of communal sharing, which means all improvements must be given back to me to be incorporated and distributed."'' The original Emacs, like TECO, ran only on the PDP-10 running ITS. Its behavior was sufficiently different from that of TECO that it could be considered a text editor in its own right, and it quickly became the standard editing program on ITS. Mike McMahon ported Emacs from ITS to the Tenex and TOPS-20 operating systems. Other contributors to early versions of Emacs include Kent Pitman, Earl Killian, and Eugene Ciccarelli. By 1979, Emacs was the main editor used in MIT's AI lab and its Computer Science lab. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Emacs」の詳細全文を読む スポンサード リンク
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