public ParseMessage Parse()
{
if (!TablesLoaded)
{
return(ParseMessage.NotLoadedError);
}
//===================================
//Loop until breakable event
//===================================
for (;;)
{
if (m_InputTokens.Count == 0)
{
Token Read = m_GroupTerminals.ProduceToken();
m_InputTokens.Push(Read);
return(ParseMessage.TokenRead);
}
else
{
Token Read = m_InputTokens.Peek();
//Update current position
if (Read.Position.HasValue)
{
m_CurrentPosition = Read.Position.Value;
}
//Runaway group
if (m_GroupTerminals.Count != 0)
{
return(ParseMessage.GroupError);
}
else if (Read.SymbolType == SymbolType.Noise)
{
//Just discard. These were already reported to the user.
m_InputTokens.Pop();
}
else if (Read.SymbolType == SymbolType.Error)
{
//Finally, we can parse the token.
return(ParseMessage.LexicalError);
}
else
{
LALRStack.ParseResult Action = m_LALRStack.ParseLALR(Read);
//SAME PROCEDURE AS v1
switch (Action)
{
case LALRStack.ParseResult.Accept:
return(ParseMessage.Accept);
case LALRStack.ParseResult.InternalError:
return(ParseMessage.InternalError);
case LALRStack.ParseResult.ReduceNormal:
return(ParseMessage.Reduction);
case LALRStack.ParseResult.Shift:
//ParseToken() shifted the token on the front of the Token-Queue.
//It now exists on the Token-Stack and must be eliminated from the queue.
m_InputTokens.Pop();
break;
case LALRStack.ParseResult.SyntaxError:
//=== Syntax Error! Fill Expected Tokens
m_ExpectedSymbols = m_LALRStack.GetExpectedSymbols();
return(ParseMessage.SyntaxError);
default:
//Do nothing.
break;
}
}
}
}
}
