Re: Van Wijngaarden grammars

fanf2@thor.cam.ac.uk (Tony Finch) wrote:
>Have any languages other than Algol68 used van Wijngaarden grammars
>for their definition?


>Has anyone written a compiler generator that uses van Wijngaarden
>grammars to describe the language to be compiled?


From: Michael Parkes <mparks@oz.net>
> Question 1: I am not aware of any.
>
> Question 2: Yes - I know of at least one but the performance was
> reported to be very slow. Most reserach seems to have focused on
> Attribute Grammars as they offer a similar (but reduced) level of
> descriptive power but are generally considered to be more usable.


re: Question 1: In my opinion, the weird formal description of Algol
68 did as much to kill the language as its unparsable grammar. (It's
still one of my favourite languages of all time!)


re: Question 2: In what sense are attribute grammars less descriptive
than VW grammars? With anything but the most trivial attribute
expressions, they can compute anything that's computable. And they're
more comprehensible to mere mortals.


--
Gordon V. Cormack CS Dept, University of Waterloo, Canada N2L 3G1
gvcormac@uwaterloo.ca http://cormack.uwaterloo.ca/~gvcormac
--

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