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[Caml-list] parsing forward references in ocamlyacc and other ocamlyacc questions
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Date: -- (:)
From: Michal Moskal <malekith@p...>
Subject: Re: [Caml-list] parsing forward references in ocamlyacc and other ocamlyacc questions
On Wed, Sep 03, 2003 at 01:31:14PM +0800, Rafael 'Dido' Sevilla wrote:
> I'm just wondering how you can guarantee that certain imperative effects
> occur, like adding a name into a symbol table hash.  I'm writing a
> compiler whose semantics allow some limited forward references, e.g.:
> 
> adt_declaration: IDENTIFIER COLON ADT OBRACE adt_member_list CBRACE SEMI
> 
> where the rules under the adt_member_list nonterminal have access to the
> identifier name given in the ADT declaration.  For the original Yacc or
> Bison, it can be done with an intermediate semantic action like:
> 
> adt_declaration: IDENTIFIER COLON ADT { Hashtbl.add symtable $1 ... } OBRACE ...
> 
> Something like (which is how you would do it without the use of
> intermediate actions):
> 
> adt_name: IDENTIFIER COLON ADT { Hashtbl.add symtable $1 adt_skel; $1 }
>   ;
> 
> adt_declaration: adt_name OBRACE adt_member_list CBRACE SEMI { ... }
>   ;
> 
> doesn't seem to work.  The symbol table addition still doesn't occur
> until after the entire adt_declaration has been parsed.  The
> documentation for ocamlyacc has very little to say about it (unless
> there's more documentation in other places besides the ocaml manual).

Are you *sure*? From what I know about yacc parser, this action *had* to
be taken before adt_member_list was parsed.

-- 
: Michal Moskal :: http://www.kernel.pl/~malekith : GCS {C,UL}++++$ a? !tv
: When in doubt, use brute force. -- Ken Thompson : {E-,w}-- {b++,e}>+++ h

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