/// <summary>
/// Raises an error on an unexepcted token
/// </summary>
/// <param name="stem">The size of the generation's stem</param>
private void OnUnexpectedToken(int stem)
{
// build the list of expected terminals
List <Symbol> expected = new List <Symbol>();
GSSGeneration genData = gss.GetGeneration();
for (int i = 0; i != genData.Count; i++)
{
LRExpected expectedOnHead = parserAutomaton.GetExpected(gss.GetRepresentedState(i + genData.Start), lexer.Terminals);
// register the terminals for shift actions
foreach (Symbol terminal in expectedOnHead.Shifts)
{
if (!expected.Contains(terminal))
{
expected.Add(terminal);
}
}
if (i < stem)
{
// the state was in the stem, also look for reductions
foreach (Symbol terminal in expectedOnHead.Reductions)
{
if (!expected.Contains(terminal) && CheckIsExpected(i + genData.Start, terminal))
{
expected.Add(terminal);
}
}
}
}
// register the error
UnexpectedTokenError error = new UnexpectedTokenError(lexer.tokens[nextToken.Index], new ROList <Symbol>(expected));
allErrors.Add(error);
#if !NETSTANDARD1_0
if (ModeDebug)
{
Console.WriteLine("==== RNGLR parsing error:");
Console.Write("\t");
Console.WriteLine(error);
TextContext context = lexer.Input.GetContext(error.Position);
Console.Write("\t");
Console.WriteLine(context.Content);
Console.Write("\t");
Console.WriteLine(context.Pointer);
gss.Print();
}
#endif
}
/// <summary>
/// Raises an error on an unexpected token
/// </summary>
/// <param name="kernel">The unexpected token's kernel</param>
/// <returns>The next token kernel in the case the error is recovered</returns>
private Lexer.TokenKernel OnUnexpectedToken(Lexer.TokenKernel kernel)
{
LRExpected expectedOnHead = automaton.GetExpected(stack[head], lexer.Terminals);
// the terminals for shifts are always expected
List <Symbol> expected = new List <Symbol>(expectedOnHead.Shifts);
// check the terminals for reductions
foreach (Symbol terminal in expectedOnHead.Reductions)
{
if (CheckIsExpected(terminal))
{
expected.Add(terminal);
}
}
// register the error
allErrors.Add(new UnexpectedTokenError(lexer.tokens[kernel.Index], new ROList <Symbol>(expected)));
// TODO: try to recover, or not
return(new Lexer.TokenKernel(Symbol.SID_NOTHING, -1));
}
/// <summary>
/// Gets the expected terminals for the specified state
/// </summary>
/// <param name="state">The DFA state</param>
/// <param name="terminals">The possible terminals</param>
/// <returns>The expected terminals</returns>
public LRExpected GetExpected(int state, ROList <Symbol> terminals)
{
LRExpected result = new LRExpected();
int offset = ncols * state;
for (int i = 0; i != terminals.Count; i++)
{
LRAction action = table[offset];
if (action.Code == LRActionCode.Shift)
{
result.Shifts.Add(terminals[i]);
}
else if (action.Code == LRActionCode.Reduce)
{
result.Reductions.Add(terminals[i]);
}
offset++;
}
return(result);
}
/// <summary>
/// Gets the expected terminals for the specified state
/// </summary>
/// <param name="state">The DFA state</param>
/// <param name="terminals">The possible terminals</param>
/// <returns>The expected terminals</returns>
public LRExpected GetExpected(int state, ROList <Symbol> terminals)
{
LRExpected result = new LRExpected();
for (int i = 0; i != terminals.Count; i++)
{
Cell cell = table[state * ncols + i];
for (int j = 0; j != cell.ActionsCount; j++)
{
LRAction action = actions[cell.ActionsIndex + j];
if (action.Code == LRActionCode.Shift)
{
result.AddUniqueShift(terminals[i]);
}
else if (action.Code == LRActionCode.Reduce)
{
result.AddUniqueReduction(terminals[i]);
}
}
}
return(result);
}
