Re: Formal semantics of language semantics

Ingo Dittmer <i.dittmer@fh-osnabrueck.de> wrote:
>Joe Hendrix schrieb:
>
>> Are there any notations commonly used to define the semantics of a
>> programming language? (Similar to how BNF defines the syntax).
>
>Many. All two-level-grammars (van-Wijngarden, affix, extended affix
>(also used to describe whole compilers formally), attribute (also for
>compilers),...), denotational semantics, fixpoint semantics, predicate
>semantics, Wiener definition method (used for PL/I), and so on and so
>on...
>
>The first developments have been in the 60th, and there are a lot of
>fine books.


Hang on. The two-level grammars that I know of DON'T handle the
semantics, but extend the syntax to things like the type rules. That
was most definitely so for the van Wijngarden grammar used in Algol
68, for example. The semantics of that were most definitely described
using hand-waving, though that aspect was no than Fortran.


My copy of the Revised Report is at work, and I can't remember if
Algol 68 even specified the rules for array bounds etc. using the
two-level grammar, but my recollection is that it didn't.


Regards,
Nick Maclaren,
University of Cambridge Computing Service,
New Museums Site, Pembroke Street, Cambridge CB2 3QH, England.
Email: nmm1@cam.ac.uk
Tel.: +44 1223 334761 Fax: +44 1223 334679

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