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TECO (; originally an acronym for ''() Tape Editor and COrrector'', but later Text Editor and COrrector'', then Text Editor Character Oriented'') is a text editor originally developed at the Massachusetts Institute of Technology (MIT) in the 1960s, after which it was modified by "just about everybody".〔 〕 TECO was a direct ancestor of Emacs, which was originally implemented in TECO macros. ==Description and impact== TECO is not only an editor but also an interpreted programming language for text manipulation. Arbitrary programs (called "macros") for searching and modifying text give it great power. Unlike regular expressions, however, the language was imperative (though some versions had an "or" operator in string search). TECO does not really have syntax; each character in a program is an imperative command, dispatched to its corresponding routine. That routine may read further characters from the program stream (giving the effect of string arguments), change the position of the "program counter" (giving the effect of control structures), or push values onto a value stack (giving the effect of nested parentheses). But there is nothing to prevent operations like jumping into the middle of a comment, since there is no syntax and no parsing. A classic essay on computer programming, Real Programmers Don't Use Pascal, suggested that a common game for TECO fans was to enter their name as a command sequence, and then try to work out what would happen. The same essay in describing TECO coined the acronym ''YAFIYGI'', meaning "You Asked For It You Got It" and thus being the antithesis of WYSIWYG ("What You See Is What You Get"). Richard Stallman's Emacs editor was originally implemented in TECO. (Later 1970s editors which preserved the UI and default-keybindings of the original EMACS were written in Lisp: EINE/ZWEI for the MIT CADR, then Multics Emacs for the IBM 360 in 1978. In the early 1980s, first Gosling Emacs, then GNU Emacs and Lucid Emacs, were implemented in C beneath a variant of Lisp.) TECO became well-known following a Digital Equipment Corporation (DEC) PDP-6 mainframe implementation developed at MIT's Project MAC in 1964. This implementation continuously displayed the edited text visually on a CRT screen, and was used as an interactive online editor (this was, however, neither its origin nor its originally intended mode of use). Later versions of TECO were capable of driving full-screen mode on various DEC RS232 video terminals such as the VT52 or VT100. TECO was available for several operating systems and computers, including the PDP-1 computer, the Incompatible Timesharing System (ITS) on the PDP-6 and PDP-10 mainframe, and TOPS-10 and TOPS-20 on the PDP-10. A version of TECO was provided with all DEC operating systems; the version available for RT11 was able to drive the GT40 graphics display while the version available for RSTS/E was implemented as a multi-user run-time system and could be used as the user's complete operating environment; the user never actually had to exit TECO. The VTEDIT (Video Terminal Editor) TECO macro was commonly used on RSTS/E and VAX systems with terminals capable of direct-cursor control (e.g. VT52 and VT100) to provide a full-screen visual editor similar in function to the contemporaneously developed Emacs. Hewlett-Packard, having bought Compaq (who bought Digital Equipment Corporation), provides TECO with the OpenVMS operating system.〔 (【引用サイトリンク】url=http://h71000.www7.hp.com/doc/83final/9996/9996pro_72.html )〕 A descendant of the version DEC distributed for the PDP-10 is still available on the Internet, along with several partial implementations for the MS-DOS/Microsoft Windows environment. 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「TECO (text editor)」の詳細全文を読む スポンサード リンク
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