public CustomParserAction(LanguageData language, ParserState state,
ExecuteActionMethod executeRef)
{
Language = language;
State = state;
ExecuteRef = executeRef;
Conflicts.UnionWith(state.BuilderData.Conflicts);
// Create default shift and reduce actions
foreach (var shiftItem in state.BuilderData.ShiftItems)
ShiftActions.Add(new ShiftParserAction(shiftItem));
foreach (var item in state.BuilderData.ReduceItems)
ReduceActions.Add(ReduceParserAction.Create(item.Core.Production));
}
//Find an LR item without hints compatible with term (either shift on term or reduce with term as lookahead);
// this item without hints would become our default. We assume that other items have hints, and when conditions
// on all these hints fail, we chose this remaining item without hints.
private ParserAction FindDefaultAction(ParserState state, BnfTerm term)
{
//First check reduce items
var reduceItems = state.BuilderData.ReduceItems.SelectByLookahead(term as Terminal);
foreach (var item in reduceItems)
if (item.Core.Hints.Count == 0)
return ReduceParserAction.Create(item.Core.Production);
var shiftItem = state.BuilderData.ShiftItems.SelectByCurrent(term).FirstOrDefault();
if (shiftItem != null)
return new ShiftParserAction(shiftItem);
//if everything failed, returned first reduce item
return null;
}
//Check if there is an action already in state for this term; if yes, and it is Conditional action,
// then simply add an extra conditional entry to it. If an action does not exist, or it is not conditional,
// create new conditional action for this term.
private void AddConditionalEntry(ParserState state, BnfTerm term, ConditionalParserAction.ConditionalEntry entry)
{
ParserAction oldAction;
ConditionalParserAction condAction = null;
if (state.Actions.TryGetValue(term, out oldAction))
condAction = oldAction as ConditionalParserAction;
if (condAction == null)
{
//there's no old action, or it is not conditional; create new conditional action
condAction = new ConditionalParserAction();
condAction.DefaultAction = oldAction;
state.Actions[term] = condAction;
}
condAction.ConditionalEntries.Add(entry);
if (condAction.DefaultAction == null)
condAction.DefaultAction = FindDefaultAction(state, term);
if (condAction.DefaultAction == null) //if still no action, then use the cond. action as default.
condAction.DefaultAction = entry.Action;
}
public ShiftParserAction(BnfTerm term, ParserState newState)
{
Term = term;
NewState = newState;
}
public SyntaxError(SourceLocation location, string message, ParserState parserState)
{
Location = location;
Message = message;
ParserState = parserState;
}
internal ParserAction(ParserState newState, Production reduceProduction, Action <ConflictResolutionArgs> conflictResolver)
: this(ParserActionType.Code, newState, reduceProduction)
{
ConflictResolver = conflictResolver;
}
public ParseTreeNode(ParserState initialState) : this()
{
State = initialState;
}
