Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cwjcc!gatech!dcatla!itwaf
From: itwaf@dcatla.UUCP (Bill Fulton [Sys Admin])
Newsgroups: comp.unix.wizards
Subject: Re: yacc reduce/reduce conflict question
Message-ID: <23311@dcatla.UUCP>
Date: 8 Sep 89 22:07:40 GMT
References: <718@larry.sal.wisc.edu> <13030009@eecs.nwu.edu>
Reply-To: dcatla!itwaf@gatech.edu (Bill Fulton [Sys Admin])
Organization: DCA Inc., Alpharetta, GA
Lines: 21

To recap; erroneous yacc input was:
 cmd : MNEMONIC = MNEMONIC ;
                ^
                Note missing quotes

I also sent the original poster this fix; but I was very surprised at the
way yacc handled the unquoted equals sign. Apparantly, when the '=' was not
quoted, yacc just *ignored* everything from the '=' to the end of the line!
This explains the conflict, but can anyone explain why yacc (apparantly)
ignores the part of a rule from an unquoted '=' to the end of line??? Does it
do this with other unquoted characters? Is an unquoted '=' special?
That's scary (e.g. silently dropping the end of a rule).

I tried different unquoted characters than a '=', and I got yacc errors, but NO
error with the unquoted '='! Also, looking at the output of 'yacc -v', I noted
that the rule for the input line with the unquoted '=' had, indeed, just
truncated the rule, starting at the '='.

waf
(Saving the net millions of dollars by not having a .sig)
(Oops - does this count?)