grammar conflicts

Jean Morissette <jean.morissette666@videotron.ca>
27 Mar 2005 17:32:03 -0500

          From comp.compilers

Related articles
grammar conflicts jean.morissette666@videotron.ca (Jean Morissette) (2005-03-27)
Re: grammar conflicts 148f3wg02@sneakemail.com (Karsten Nyblad) (2005-03-31)
Re: grammar conflicts cfc@shell01.TheWorld.com (Chris F Clark) (2005-03-31)
Re: grammar conflicts xous@xouslab.com (Xous - Jose R. Negreira) (2005-03-31)
| List of all articles for this month |

From: Jean Morissette <jean.morissette666@videotron.ca>
Newsgroups: comp.compilers
Date: 27 Mar 2005 17:32:03 -0500
Organization: Compilers Central
Keywords: parse, question

Hi,
I'm playing with JavaCUP and encounter some conflicts with my grammar (see
below) and I don't know how to resolve these conflicts. Any help would be
greatly appreciated.


Thank
-Jean


main ::=
                                identifier_chain
                | qualified_asterisk
                ;


identifier_chain ::=
                                identifier_chain PERIOD identifier
                | identifier
                ;


qualified_asterisk ::=
                                asterisked_identified_chain PERIOD asterisk
                ;


asterisked_identified_chain ::=
                                asterisked_identified_chain PERIOD
                | identifier
                ;




    *** Reduce/Reduce conflict found in state #5
    between asterisked_identified_chain ::= identifier (*)
    and identifier_chain ::= identifier (*)
    under symbols: {PERIOD}
    Resolved in favor of the second production.


    *** Shift/Reduce conflict found in state #5
    between asterisked_identified_chain ::= identifier (*)
    under symbol PERIOD
    Resolved in favor of shifting.


    *** Shift/Reduce conflict found in state #5
    between identifier_chain ::= identifier (*)
    under symbol PERIOD
    Resolved in favor of shifting.


    Checking for non-reduced productions...
    *** Production "asterisked_identified_chain ::= identifier " never reduced
[It's the usual LALR problem, the parser has to look more than one
token ahead to figure out what it's parsing. In this case,
identified_chain and asterisked_identified_chain are too similar. I'd
suggest combining them and tell the difference semantically. -John]



Post a followup to this message

Return to the comp.compilers page.
Search the comp.compilers archives again.