:
Icon is a
very high-level programming language based on the concept of "goal-directed execution" in which code returns a "success" along with valid values, or a "failure", indicating that there is no valid data to return. The success and failure of a given block of code is used to direct further processing, whereas conventional languages would typically use
boolean logic
In mathematics and mathematical logic, Boolean algebra is a branch of algebra. It differs from elementary algebra in two ways. First, the values of the variable (mathematics), variables are the truth values ''true'' and ''false'', usually denote ...
written by the programmer to achieve the same ends. Because the logic for basic control structures is often implicit in Icon, common tasks can be completed with less explicit code.
Icon was designed by
Ralph Griswold after leaving
Bell Labs where he was a major contributor to the
SNOBOL language. SNOBOL was a string-processing language with what would be considered dated syntax by the standards of the early 1970s. After moving to the
University of Arizona, he further developed the underlying SNOBOL concepts in SL5, but considered the result to be a failure. This led to the significantly updated Icon, which blends the short but conceptually dense code of SNOBOL-like languages with the more familiar syntax of
ALGOL-inspired languages like
C or
Pascal
Pascal, Pascal's or PASCAL may refer to:
People and fictional characters
* Pascal (given name), including a list of people with the name
* Pascal (surname), including a list of people and fictional characters with the name
** Blaise Pascal, Fren ...
.
Like the languages that inspired it, the primary area of use of Icon is managing
strings
String or strings may refer to:
*String (structure), a long flexible structure made from threads twisted together, which is used to tie, bind, or hang other objects
Arts, entertainment, and media Films
* ''Strings'' (1991 film), a Canadian anim ...
and textual patterns. String operations often fail, for instance, finding "the" in "world". In most languages, this requires testing and branching to avoid using a non-valid result. In Icon most of these sorts of tests are simply not required, reducing the amount of code written by the programmer. Complex pattern handling can be accomplished in a few lines of terse code, similar to more dedicated languages like
Perl but retaining a more function-oriented syntax familiar to users of other ALGOL-like languages.
Icon is not