private LookAheadSet FindLookAhead(ProductionPatternElement elem,
int length,
int dummy,
CallStack stack,
LookAheadSet filter)
{
LookAheadSet result;
if (elem.IsToken())
{
result = new LookAheadSet(length);
result.Add(elem.Id);
}
else
{
var pattern = GetPattern(elem.Id);
result = FindLookAhead(pattern, length, stack, filter);
if (stack.Contains(pattern.Name))
{
result = result.CreateRepetitive();
}
}
return(result);
}
private void ParseElement(Production node,
ProductionPatternElement elem)
{
for (int i = 0; i < elem.MaxCount; i++)
{
if (i < elem.MinCount || IsNext(elem))
{
Node child;
if (elem.IsToken())
{
child = NextToken(elem.Id);
EnterNode(child);
AddNode(node, ExitNode(child));
}
else
{
child = ParsePattern(GetPattern(elem.Id));
AddNode(node, child);
}
}
else
{
break;
}
}
}
private void CheckElement(string name,
ProductionPatternElement elem)
{
if (elem.IsProduction() && GetPattern(elem.Id) == null)
{
throw new ParserCreationException(
ParserCreationException.ErrorType.INVALID_PRODUCTION,
name,
"an undefined production pattern id (" + elem.Id +
") is referenced");
}
}
public void AddElement(ProductionPatternElement elem,
int min,
int max)
{
if (elem.IsToken())
{
AddToken(elem.Id, min, max);
}
else
{
AddProduction(elem.Id, min, max);
}
}
private LookAheadSet FindLookAhead(ProductionPatternElement elem,
int length,
CallStack stack,
LookAheadSet filter)
{
// Find initial element look-ahead
var first = FindLookAhead(elem, length, 0, stack, filter);
var result = new LookAheadSet(length);
result.AddAll(first);
if (filter == null || !filter.IsOverlap(result))
{
return(result);
}
// Handle element repetitions
if (elem.MaxCount == Int32.MaxValue)
{
first = first.CreateRepetitive();
}
var max = elem.MaxCount;
if (length < max)
{
max = length;
}
for (int i = 1; i < max; i++)
{
first = first.CreateOverlaps(filter);
if (first.Size() <= 0 || first.GetMinLength() >= length)
{
break;
}
var follow = FindLookAhead(elem,
length,
0,
stack,
filter.CreateFilter(first));
first = first.CreateCombination(follow);
result.AddAll(first);
}
return(result);
}
private bool IsNext(ProductionPatternElement elem)
{
LookAheadSet set = elem.LookAhead;
if (set != null)
{
return(set.IsNext(this));
}
else if (elem.IsToken())
{
return(elem.IsMatch(PeekToken(0)));
}
else
{
return(IsNext(GetPattern(elem.Id)));
}
}
private string ToString(ProductionPatternElement elem)
{
StringBuilder buffer = new StringBuilder();
int min = elem.MinCount;
int max = elem.MaxCount;
if (min == 0 && max == 1)
{
buffer.Append("[");
}
if (elem.IsToken())
{
buffer.Append(GetTokenDescription(elem.Id));
}
else
{
buffer.Append(GetPattern(elem.Id).Name);
}
if (min == 0 && max == 1)
{
buffer.Append("]");
}
else if (min == 0 && max == Int32.MaxValue)
{
buffer.Append("*");
}
else if (min == 1 && max == Int32.MaxValue)
{
buffer.Append("+");
}
else if (min != 1 || max != 1)
{
buffer.Append("{");
buffer.Append(min);
buffer.Append(",");
buffer.Append(max);
buffer.Append("}");
}
return(buffer.ToString());
}
public void AddElement(ProductionPatternElement elem)
{
_elements.Add(elem);
}