Computing Dictionary
Icon definition
language A descendant of
SNOBOL4 with
Pascal-like syntax, produced by Griswold in the 1970's. Icon is a general-purpose language with special features for string scanning. It has dynamic types: records, sets, lists, strings, tables. If has some
object oriented features but no
modules or
exceptions. It has a primitive
Unix interface.
The central theme of Icon is the generator: when an expression is evaluated it may be suspended and later resumed, producing a result sequence of values until it fails. Resumption takes place implicitly in two contexts: iteration which is syntactically loop-like ('every-do'), and goal-directed evaluation in which a conditional expression automatically attempts to produce at least one result. Expressions that fail are used in lieu of Booleans. Data
backtracking is supported by a reversible
assignment. Icon also has
co-expressions, which can be explicitly resumed at any time.
Version 8.8 by Ralph Griswold
includes an interpreter, a compiler (for some platforms) and a library (v8.8). Icon has been ported to Amiga, Atari, CMS, Macintosh, Macintosh/MPW, MS-DOS, MVS, OS/2, Unix, VMS, Acorn.
See also Ibpag2.
(ftp://cs.arizona.edu/icon/), MS-DOS FTP (ftp://bellcore.com norman/iconexe.zip).
Usenet newsgroup: news:comp.lang.icon.
E-mail: , .
Mailing list: icon-group@arizona.edu.
["The Icon Programmming Language", Ralph E. Griswold and Madge T. Griswold, Prentice Hall, seond edition, 1990].
["The Implementation of the Icon Programmming Language", Ralph E. Griswold and Madge T. Griswold, Princeton University Press 1986].
(1992-08-21)