Article View: comp.lang.prolog
Article #270Re: Bootstrapping precedence grammars.
From: Jiyang Xu
Date: Fri, 04 Aug 1989 08:21
Date: Fri, 04 Aug 1989 08:21
19 lines
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1444 bytes
In article <3635@csd4.milw.wisc.edu>, markh@csd4.milw.wisc.edu (Mark William Hopkins) writes:
> Can Prolog's read(X) predicate be defined using only the character
> predicates for I/O? In other words, does Prolog have the capacity to
> bootstrap its own precedence grammar, using the operator declarations
> made by the op predicate?
Certainly you can, as defined in the famous O'Keefe's reader, which
is also used in SB-Prolog and possibly many other Prologs.
> op(Prec, Type, Rator)
>
> cannot be used in the mode
>
> op(OUTPUT, OUTPUT, INPUT),
There is another predicate "current_op/3" for this purpose.
The predicate is implemented in most Prolog systems.
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!gem.mps.ohio-state.edu!ginosko!uunet!mcvax!unido!ecrcvax!jiyang From: jiyang@ecrcvax.UUCP (Jiyang Xu) Newsgroups: comp.lang.prolog Subject: Re: Bootstrapping precedence grammars. Summary: Implement read(X) in Prolog Message-ID: <752@ecrcvax.UUCP> Date: 4 Aug 89 08:21:23 GMT References: <3635@csd4.milw.wisc.edu> Organization: ECRC, Munich 81, West Germany Lines: 19