Van Wijngaarden grammars

> Have any languages other than Algol68 used van Wijngaarden grammars
> for their definition?


Ponder (a declarative polymorphic language from Jon Fairbairn,
Uni. Cambridge Comp. Labs).


But in fact I have seen the ideas of two-level grammars sneaking into
a lot of language descriptions - at least as far as attributing
productions with the type of the value (l or r) as a very concise way
of saying types must match, but I have only seen A68 and Ponder use
them to define how coercions work, require only a single declaration
of an identifier in a range, require visible declarations, etc.
Although some of these formalisms were not in the 1968 only the 1973
description providing, IMO, unnecessary obfuscation albeit greater
formal definition.


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Dave Lloyd Email: Dave@occl-cam.demon.co.uk
Oxford and Cambridge Compilers Ltd Phone: (44) 1223 572074
55 Brampton Rd, Cambridge CB1 3HJ, UK
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