private void AddLalrTable(int p_index, LRActionTable p_table)
{
if (!m_initialized)
{
throw new ParserException("Table counts not initialized");
}
m_LalrTables[p_index] = p_table;
}
/// This function analyzes a token and either:
/// 1. Makes a SINGLE reduction and pushes a complete Reduction object on the stack
/// 2. Accepts the token and shifts
/// 3. Errors and places the expected symbol indexes in the Tokens list
/// The Token is assumed to be valid and WILL be checked
private ParseResult ParseToken(Token p_token)
{
ParseResult result = ParseResult.InternalError;
LRActionTable table = m_LalrTables[m_LalrState];
LRAction action = table.GetActionForSymbol(p_token.TableIndex);
if (action != null)
{
m_haveReduction = false;
m_outputTokens.Clear();
switch (action.Action)
{
case Action.Accept:
m_haveReduction = true;
result = ParseResult.Accept;
break;
case Action.Shift:
p_token.State = m_LalrState = action.Value;
m_tempStack.PushToken(p_token);
result = ParseResult.Shift;
break;
case Action.Reduce:
result = Reduce(m_rules[action.Value]);
break;
}
}
else
{
// syntax error - fill expected tokens.
m_outputTokens.Clear();
foreach (LRAction a in table.Members)
{
SymbolType kind = a.Symbol.Kind;
if (kind == SymbolType.Terminal || kind == SymbolType.End)
{
m_outputTokens.PushToken(new Token(a.Symbol));
}
}
result = ParseResult.SyntaxError;
}
return(result);
}
private void LoadTables(GrammarReader reader)
{
Object obj; Int16 index;
while (reader.MoveNext())
{
byte id = (byte)reader.RetrieveNext();
switch ((RecordId)id)
{
case RecordId.Parameters:
m_parameters["Name"] = (String)reader.RetrieveNext();
m_parameters["Version"] = (String)reader.RetrieveNext();
m_parameters["Author"] = (String)reader.RetrieveNext();
m_parameters["About"] = (String)reader.RetrieveNext();
m_caseSensitive = (Boolean)reader.RetrieveNext();
m_startSymbol = (Int16)reader.RetrieveNext();
break;
case RecordId.TableCounts:
m_symbols = new Symbol[(Int16)reader.RetrieveNext()];
m_charsets = new String[(Int16)reader.RetrieveNext()];
m_rules = new Rule[(Int16)reader.RetrieveNext()];
m_DfaStates = new FAState[(Int16)reader.RetrieveNext()];
m_LalrTables = new LRActionTable[(Int16)reader.RetrieveNext()];
m_initialized = true;
break;
case RecordId.Initial:
m_initDfaState = (Int16)reader.RetrieveNext();
m_initLalrState = (Int16)reader.RetrieveNext();
break;
case RecordId.Symbols:
index = (Int16)reader.RetrieveNext();
String name = (String)reader.RetrieveNext();
SymbolType kind = (SymbolType)(Int16)reader.RetrieveNext();
Symbol symbol = new Symbol(index, name, kind);
AddSymbol(symbol);
break;
case RecordId.CharSets:
index = (Int16)reader.RetrieveNext();
String charset = (String)reader.RetrieveNext();
AddCharset(index, charset);
break;
case RecordId.Rules:
index = (Int16)reader.RetrieveNext();
Symbol head = m_symbols[(Int16)reader.RetrieveNext()];
Rule rule = new Rule(index, head);
reader.RetrieveNext(); // reserved
while ((obj = reader.RetrieveNext()) != null)
{
rule.AddItem(m_symbols[(Int16)obj]);
}
AddRule(rule);
break;
case RecordId.DFAStates:
FAState fastate = new FAState();
index = (Int16)reader.RetrieveNext();
if ((bool)reader.RetrieveNext())
{
fastate.AcceptSymbol = (Int16)reader.RetrieveNext();
}
else
{
reader.RetrieveNext();
}
reader.RetrieveNext(); // reserverd
while (!reader.RetrieveDone())
{
Int16 ci = (Int16)reader.RetrieveNext();
Int16 ti = (Int16)reader.RetrieveNext();
reader.RetrieveNext(); // reserved
fastate.AddEdge(m_charsets[ci], ti);
}
AddDfaState(index, fastate);
break;
case RecordId.LRTables:
LRActionTable table = new LRActionTable();
index = (Int16)reader.RetrieveNext();
reader.RetrieveNext(); // reserverd
while (!reader.RetrieveDone())
{
Int16 sid = (Int16)reader.RetrieveNext();
Int16 action = (Int16)reader.RetrieveNext();
Int16 tid = (Int16)reader.RetrieveNext();
reader.RetrieveNext(); // reserved
table.AddItem(m_symbols[sid], (Action)action, tid);
}
AddLalrTable(index, table);
break;
case RecordId.Comment:
Console.WriteLine("Comment record encountered");
break;
default:
throw new ParserException("Wrong id for record");
}
}
}