Interpreting shift/reduce conflicts from .output file

[Frans Englich]

Hi,

In my grammar I have 2 shift/reduce conflicts. I could find those by staring 
at my grammar until I find where I introduced it, but I thought I could learn 
to make use of Bison's nifty debugging -- the output file.

At the top of my .output file it says:

State 118 conflicts: 2 shift/reduce


And state 118 looks like this:

---------------------------------------------------
state 118

   72 SequenceType: ItemType .
   73             | ItemType . STAR
   74             | ItemType . PLUS
   75             | ItemType . QUESTION_MARK

    PLUS           shift, and go to state 134
    STAR           shift, and go to state 135
    QUESTION_MARK  shift, and go to state 136

    PLUS      [reduce using rule 72 (SequenceType)]
    STAR      [reduce using rule 72 (SequenceType)]
    $default  reduce using rule 72 (SequenceType)

---------------------------------------------------
State 134, 135, and 136 looks all very similar. For example, state 134 looks 
like this:

state 134

   74 SequenceType: ItemType PLUS .

    $default  reduce using rule 74 (SequenceType)


I fail to understand what is the problem, and hence how to fix it. AFAICT, 
both (for example) state 134 and 118 reduces the tokens to a SequenceType. I 
don't see where the ambiguity is. I'm neither fully sure about what the 
brackets are communicating in state 118.

Perhaps my confusion can be cleared from what I've written so far?

For those interested, the grammar can be found here:

http://websvn.kde.org/*checkout*/branches/work/kdom/xpath/impl/parser/Parser.output?rev=424401
http://websvn.kde.org/*checkout*/branches/work/kdom/xpath/impl/parser/Parser.ypp?rev=424401


Cheers,

                Frans