public static bool OverlapsAt(this ILexResult result, int position, int length)
{
int end = position + length;
// has some length
if (length > 0)
{
return((position >= result.Start && position < result.GetEnd()) ||
(end > result.Start && end <= result.GetEnd()));
}
// zero-length nodes
else if (length == 0)
{
return(position > result.Start && position < result.GetEnd());
}
// negative lengths canceled
else
{
throw new InvalidOperationException("Negative lengths not allowed.");
}
}
public static bool IsInside(this ILexResultGroup group, ILexResult target)
{
int targetEnd = target.GetEnd();
if ((target.Start >= group.Start && target.Start <= group.GetEnd()) &&
(targetEnd >= group.Start && targetEnd <= group.GetEnd()))
{
return(true);
}
else
{
return(false);
}
}
public ILexResult Match(string target)
{
// if no rules, no match
if (_rules.Count == 0)
{
return(LexNode.NoMatch);
}
LexResultGroup group = new LexResultGroup(MatchType);
group.RequiresFilledSpace = true;
// get first match, then offset
ILexResult firstResult = _rules[0].Match(target);
if (!firstResult.IsSuccessful())
{
return(LexNode.NoMatch);
}
string eaten = target.Clone() as string;
group.Start = firstResult.Start;
group.Add(firstResult);
// eat the string until after the match
eaten = eaten.Remove(0, firstResult.GetEnd());
int offset = firstResult.GetEnd();
// go through each match after the first
for (int i = 1; i < Count; i++)
{
ILexResult result = _rules[i].Match(eaten);
// ensure all pieces in the sequence succeed
if (result.IsSuccessful())
{
// matches must be "squared up"
if (result.Start != 0)
{
// wrap group as a partial result
return(LayeredLexNode.CreatePartial(group));
}
else
{
// eat the string
eaten = eaten.Remove(0, result.GetEnd());
// store an offset copy to the group
group.Add(result.Offset(offset));
// offset the offset
offset += result.GetEnd();
}
}
else if (result.MatchType == LexMatchType.Invalid)
{
return(result.Offset(offset));
}
else
{
return(LexNode.NoMatch);
}
}
return(group);
}