Re: [Caml-list] debugging an ocamlyacc parser

[Hendrik Tews <tews@tcs.inf.tu-dresden.de>]

Hi,

Rafael 'Dido' Sevilla writes:
   Date: Tue, 23 Oct 2001 10:14:42 +0800
   Subject: [Caml-list] debugging an ocamlyacc parser
   
   I'm just wondering if there's a debug mode available for
   ocamlyacc-generated parsers, like the debugging mode that Bison uses
   when you do a #define YYDEBUG, printing out all the states the parser

   
I was also missing the YYDEBUG. My workaround looks as follows:

In the header of grammar.mly:

  let d s =
    if debug_level _DEBUG_PARSER
    then begin
      prerr_string ("REDUCE " ^ s ^ "\n");
      flush stderr
    end;;

a typical rule looks like 

    signaturetype:
	TYPE ID	 		{ d "signaturetype";
				  do_sig_type_decl $2;
			        }
    ;

The lexer uses the same schema:

  let d s =
    if debug_level _DEBUG_LEXER
    then begin
      prerr_string ("SHIFT " ^ s ^ "\n");
      flush stderr
    end

and 

     | '='			{ d "Equal"; 
				  EQUAL }


_DEBUG_PARSER and _DEBUG_LEXER are constants and the return value
of the debug_level function can be influenced via a command line
switch.

Bye,

Hendrik
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