History of the Scheme programming language: Difference between revisions

Revision as of 21:19, 16 August 2024

Revision as of 21:47, 10 March 2025

Line 21:

===ALGOL===

{{Details|ALGOL}}

[[ALGOL 58]], originally to be called IAL for "International Algorithmic Language", was developed jointly by a committee of European and American computer scientists in a meeting in 1958 at [[ETH Zurich]]. [[ALGOL 60]], a later revision developed at the ALGOL 60 meeting in Paris and now commonly named [[ALGOL]], became the standard for the publication of algorithms and had a profound effect on future language development, despite the language's lack of commercial success and its limitations. [[Tony Hoare]] has remarked: "Here is a language so far ahead of its time that it was not only an improvement on its predecessors but also on nearly all its successors."<ref>{{cite book |last=Hoare |first=Tony |author-link=Tony Hoare |date=December 1973 |title=Hints on Programming Language Design |url=http://www.eecs.umich.edu/~bchandra/courses/papers/Hoare_Hints.pdf |page=27 }} (This statement is sometimes erroneously attributed to [[Edsger W. Dijkstra]], also involved in implementing the first ALGOL 60 [[compiler]].)</ref>

ALGOL introduced the use of block structure and lexical scope. It was also notorious for its difficult [[call by name]] default parameter passing mechanism, which was defined so as to require textual substitution of the expression representing the working parameter in place of the formal parameter during execution of a procedure or function, causing it to be re-evaluated each time it is referenced during execution. ALGOL implementors developed a mechanism they called a [[thunk]], which captured the context of the working parameter, enabling it to be evaluated during execution of the procedure or function.