public void RegisterPunctuation(params string[] symbols)
{
foreach (string symbol in symbols)
{
SymbolTerminal term = SymbolTerminal.GetSymbol(symbol);
term.SetOption(TermOptions.IsPunctuation);
}
}
}//method
public void RegisterBracePair(string openBrace, string closeBrace)
{
SymbolTerminal openS = SymbolTerminal.GetSymbol(openBrace);
SymbolTerminal closeS = SymbolTerminal.GetSymbol(closeBrace);
openS.SetOption(TermOptions.IsOpenBrace);
openS.IsPairFor = closeS;
closeS.SetOption(TermOptions.IsCloseBrace);
closeS.IsPairFor = openS;
}
public void RegisterOperators(int precedence, Associativity associativity, params string[] opSymbols)
{
foreach (string op in opSymbols)
{
SymbolTerminal opSymbol = SymbolTerminal.GetSymbol(op);
opSymbol.SetOption(TermOptions.IsOperator, true);
opSymbol.Precedence = precedence;
opSymbol.Associativity = associativity;
}
}//method
} //method
#endregion
#region Check for shift-reduce conflicts
private void CheckActionConflicts()
{
StringDictionary errorTable = new StringDictionary();
foreach (ParserState state in Data.States)
{
foreach (ActionRecord action in state.Actions.Values)
{
//1. Pure shift
if (action.NewState != null && action.ReduceProductions.Count == 0)
{
continue; //ActionType is shift by default
}
//2. Pure reduce
if (action.NewState == null && action.ReduceProductions.Count == 1)
{
action.ActionType = ParserActionType.Reduce;
continue;
}
//3. Shift-reduce conflict
if (action.NewState != null && action.ReduceProductions.Count > 0)
{
//it might be an operation, with resolution by precedence/associativity
SymbolTerminal opTerm = SymbolTerminal.GetSymbol(action.Key);
if (opTerm != null && opTerm.IsSet(TermOptions.IsOperator))
{
action.ActionType = ParserActionType.Operator;
}
else
{
AddErrorForInput(errorTable, action.Key, "Shift-reduce conflict in state {0}, reduce production: {1}",
state, action.ReduceProductions[0]);
//NOTE: don't do "continue" here, we need to proceed to reduce-reduce conflict check
} //if...else
} //if action....
//4. Reduce-reduce conflicts
if (action.ReduceProductions.Count > 1)
{
AddErrorForInput(errorTable, action.Key, "Reduce-reduce conflict in state {0} in productions: {1} ; {2}",
state, action.ReduceProductions[0], action.ReduceProductions[1]);
}
} //foreach action
} //foreach state
//copy errors to Errors collection; In errorTable keys are error messages, values are inputs for this message
foreach (string msg in errorTable.Keys)
{
Data.Errors.Add(msg + " on inputs: " + errorTable[msg]);
}
}//methods
public static SymbolTerminal GetSymbol(string symbol, string name)
{
SymbolTerminal term;
if (_symbols.TryGetValue(symbol, out term))
{
//rename symbol if name is provided explicitly (different from symbol itself)
if (name != symbol && term.Name != name)
{
term.Name = name;
}
return(term);
}
string.Intern(symbol);
term = new SymbolTerminal(symbol, name);
term.SetOption(TermOptions.IsGrammarSymbol, true);
_symbols[symbol] = term;
return(term);
}
public static BnfExpression operator |(string symbol1, BnfTerm term2)
{
return(Op_Pipe(SymbolTerminal.GetSymbol(symbol1), term2));
}
public static BnfExpression operator |(BnfTerm term1, string symbol2)
{
return(Op_Pipe(term1, SymbolTerminal.GetSymbol(symbol2)));
}
protected static SymbolTerminal Symbol(string symbol, string name)
{
return(SymbolTerminal.GetSymbol(symbol, name));
}
protected static SymbolTerminal Symbol(string symbol)
{
return(SymbolTerminal.GetSymbol(symbol));
}
