public void AddFirst(DotItem item, MutableIntSet output)
{
bool isNullable = tables.AddFirst(item.GetPattern(), item.Position, output);
if (isNullable)
{
output.AddAll(item.LA);
}
}
public DotTransition(MutableIntSet tokens, DotState to)
{
this.Tokens = tokens;
this.To = to;
}
/// <summary>
/// Firsts set of the token chain
/// </summary>
/// <param name="tokenChain"></param>
/// <param name="output"></param>
/// <returns><c>true</c> if chain is nullable, <c>false</c> otherwise</returns>
public bool AddFirst(int[] tokenChain, int startIndex, MutableIntSet output)
{
bool result = true;
while (startIndex != tokenChain.Length)
{
int token = tokenChain[startIndex];
output.AddAll(firsts[token]);
if (!isNullable[token])
{
result = false;
break;
}
++startIndex;
}
return result;
}
// Fill FIRST set for the chain of tokens.
// Returns true if anything was added, false otherwise.
private bool InternalAddFirsts(IEnumerable<int> chain, MutableIntSet result)
{
bool changed = false;
bool nullable = true;
foreach (int item in chain)
{
bool itemNullable = false;
foreach (var f in firsts[item].ToArray())
{
if (f == PredefinedTokens.Epsilon)
{
itemNullable = true; // current part is nullable
continue;
}
if (!result.Contains(f))
{
result.Add(f);
changed = true;
}
}
if (!itemNullable)
{
nullable = false;
break;
}
}
if (nullable && !result.Contains(PredefinedTokens.Epsilon))
{
result.Add(PredefinedTokens.Epsilon);
changed = true;
}
return changed;
}
public TdfaTransition(int from, MutableIntSet symbols, int to)
{
From = from;
Symbols = symbols;
To = to;
}
