NPL (programming language): Difference between revisions

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{{for|other programming languages and concepts abbreviated as NPL|NPL (disambiguation)}}

{{cleanup-date|November 2005}}

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:''At least three unrelated programming languages have had the name '''NPL'''.''

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{{More footnotes|date=July 2019}}

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'''NPL''' wasis a [[Functional programming|functional programming language]] with [[pattern matching]] designed by [[Rod Burstall]] and [[John Darlington]] in 1977. The language allowedallows certain sets and logic constructs to appear on the right -hand side of definitions, Ee.g.

'''NPL''' (possibly for '''N'''ew '''P'''rogramming '''L'''anguage) was the original name given to what would later become [[IBM]]'s [[PL/I]] programming language.

The 'NPL' name was in effect between [[March 1]] and [[November 30]], [[1964]]. The name was changed to avoid collision with the [[National Physical Laboratory]]. MPL and MPPL were considered before settling on PL/I.

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'''NPL''' was a [[functional language]] with [[pattern matching]] designed by Rod Burstall and John Darlington in 1977. The language allowed certain sets and logic constructs to appear on the right hand side of definitions, E.g.

setofeven(X) <= <:x: x in X & even(x) :>

The NPL interpreter evaluates the list of generators from left to right so conditions can mention any bound variables that occur to their left. These were known as [[set comprehensionscomprehension]]s. NPL eventually evolved into [[Hope programming language|Hope]] but lost set comprehensions, which weremade calleda reappearance in the form of [[list comprehension]]s in later functional languages.<ref name="foldoc">{{foldoc|NPL}}</ref>

''Reference: John Darlington, "Program Transformation and Synthesis: Present Capabilities", Research Report No. 77/43, Dept. of Computing and Control, Imperial College of Science and Technology, London September 1977.''

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'''NPL''' (for '''NonProcedural Language''') was a [[relational database]] language developed by T.D. Truitt et al in 1980 for [[Apple II]] and [[MS-DOS]].

''Reference: "An Introduction to Nonprocedural Languages Using NPL", T.D. Truitt et al, McGraw-Hill 1983.''

==References==

{{Reflist}}

''Reference:* John Darlington, (1977). "Program Transformation and Synthesis: Present Capabilities",. Research Report No. 77/43, Dept. of Computing and Control, Imperial College of Science and Technology, London September 1977.''

[[Category:HistoricalAcademic programming languages]]

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[[Category:PL/IFunctional dialectslanguages]]

[[Category:History of computing in the United Kingdom]]

[[Category:Historical programming languages]]

[[Category:PL/I dialects]]

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