TECO
/tee'koh/ obsolete [originally an acronym for "[paper] Tape
Editor and COrrector"; later, "Text Editor and COrrector"] A
text editor developed at MIT and modified by just about
everybody. With all the dialects included, TECO may have been
the most prolific editor in use before {Emacs}, to which it
was directly ancestral. The first {Emacs} editor was written
in TECO.
It was noted for its powerful programming-language-like
features and its unspeakably hairy syntax. TECO programs are
said to resemble {line noise}. It is literally the case that
every string of characters is a valid TECO program (though
probably not a useful one); one common game used to be
mentally working out what the TECO commands corresponding to
human names did.
As an example of TECO's obscurity, here is a TECO program that
takes a list of names such as:
Loser, J. Random
Quux, The Great
Dick, Moby
sorts them alphabetically according to surname, and then puts
the surname last, removing the comma, to produce the
following:
Moby Dick
J. Random Loser
The Great Quux
The program is
[1 J^P$L$$
J <.-Z; .,(S,$ -D .)FX1 ◊F^B $K :L I $ G1 L>$$
(where ^B means "Control-B" (ASCII 0000010) and $ is actually
an {alt} or escape (ASCII 0011011) character).
In fact, this very program was used to produce the second,
sorted list from the first list. The first hack at it had a
{bug}: GLS (the author) had accidentally omitted the "◊" in
front of "F^B", which as anyone can see is clearly the {Wrong
Thing}. It worked fine the second time. There is no space to
describe all the features of TECO, but it may be of interest
that "^P" means "sort" and "J<.-Z; ... L>" is an idiomatic
series of commands for "do once for every line".
In mid-1991, TECO is pretty much one with the dust of history,
having been replaced in the affections of hackerdom by
{Emacs}. Descendants of an early (and somewhat lobotomised)
version adopted by DEC can still be found lurking on VMS and a
couple of crufty {PDP-11} {operating system}s, however, and
ports of the more advanced MIT versions remain the focus of
some antiquarian interest. See also {retrocomputing},
{write-only language}.
{(ftp://usc.edu/)} for {VAX}/{VMS}, {Unix}, {MS-DOS},
{Macintosh}, {Amiga}.