Editing Icon (programming language) (section)

===SL5 leads to Icon===
Griswold left Bell Labs to become a professor at the [[University of Arizona]] in August 1971.{{sfn|Griswold|1981|pp=609}} He introduced SNOBOL4 as a research tool at that time.{{sfn|Griswold|1981|pp=629}} He received grants from the [[National Science Foundation]] to continue supporting and evolving SNOBOL.{{sfn|Shapiro|1985|pp=346}}

As a language originally developed in the early 1960s, SNOBOL's syntax bears the marks of other early programming languages like [[FORTRAN]] and [[COBOL]]. In particular, the language is column-dependant, as many of these languages were entered on [[punch card]]s where column layout is natural. Additionally, control structures were almost entirely based on branching around code rather than the use of [[Block (programming)|blocks]], which were becoming a must-have feature after the introduction of [[ALGOL 60]]. By the time he moved to Arizona, the syntax of SNOBOL4 was hopelessly outdated.{{sfn|Griswold|Griswold|1993|p=53}}

Griswold began the effort of implementing SNOBOL's underlying success/failure concept with traditional flow control structures like if/then. This became SL5, short for "SNOBOL Language 5", but the result was unsatisfying.{{sfn|Griswold|Griswold|1993|p=53}} In 1977, he returned to the language to consider a new version. He abandoned the very powerful function system introduced in SL5 with a simpler concept of suspend/resume and developed a new concept for the natural successor to SNOBOL4 with the following principles;{{sfn|Griswold|Griswold|1993|p=53}}

* SNOBOL4's philosophic and sematic basis
* SL5 syntactic basis
* SL5 features, excluding the generalized procedure mechanism

The new language was initially known as SNOBOL5, but as it was significantly different from SNOBOL in all but the underlying concept, a new name was ultimately desired. After considering "s" as a sort of homage to "C", but this was ultimately abandoned due to the problems with typesetting documents using that name. A series of new names were proposed and abandoned; Irving, bard, and "TL" for "The Language". It was at this time that [[Xerox PARC]] began publishing about their work on [[graphical user interface]]s and the term "icon" began to enter the computer lexicon. The decision was made to change the name initially to "icon" before finally choosing "Icon".{{sfn|Griswold|Griswold|1993|p=53}}{{efn|According to an interview in 1985, Griswold states that the term 'icon' was not being used until [[Smalltalk]] was released to the public some time later. He expressed his annoyance that the term was now confusing people who thought the language had graphical elements.{{sfn|Shapiro|1985|p=350}}}}