private bool ResolveConflictByPrecedence(ParserState state, BnfTerm conflict)
{
var stateData = state.BuilderData;
if (!conflict.IsSet(TermOptions.UsePrecedence))
{
return(false);
}
if (!stateData.ShiftTerms.Contains(conflict))
{
return(false); //it is not shift-reduce
}
//first find reduce items
var reduceItems = stateData.ReduceItems.SelectByLookahead(conflict);
if (reduceItems.Count > 1)
{
return(false); // if it is reduce-reduce conflict, we cannot fix it by precedence
}
var reduceItem = reduceItems.First();
//remove shift action and replace it with operator action
var oldAction = state.Actions[conflict];
var action = ParserAction.CreateOperator(oldAction.NewState, reduceItem.Core.Production);
state.Actions[conflict] = action;
stateData.ResolvedConflicts.Add(conflict);
return(true);
}