History of the Scheme programming language: Difference between revisions

Revision as of 23:57, 15 October 2009

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===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|ALGOL 60]], a later revision developed at the ALGOL 60 meeting in Paris and now commonly known as 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. [[C. A. R. 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>[http://www.eecs.umich.edu/~bchandra/courses/papers/Hoare_Hints.pdf "Hints on Programming Language Design"], C.A.R. Hoare, December 1973. 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 actual 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 actual parameter, enabling it to be evaluated during execution of the procedure or function.

==Carl Hewitt, the Actor model, and the birth of Scheme==