public QuantifierStackFrame(StackFrame parent, QuantifierPattern quant)
: this(parent, new RepeaterConsList <BasePattern>(quant.ChildPattern, quant.MaxOccurrences), quant.IsGreedy, -1)
{
if (quant.MinOccurrences != 0)
{
quant.AssertCanonicalForm();
}
}
private BasePattern reduceQuantifier(QuantifierPattern quant)
{
if (quant.MaxOccurrences == 0)
return GroupPattern.Empty;
else if (quant.MinOccurrences == 1 && quant.MaxOccurrences == 1)
return quant.ChildPattern;
else
return quant;
}
private BasePattern reduceQuantifier(QuantifierPattern quant)
{
if (quant.MaxOccurrences == 0)
{
return(GroupPattern.Empty);
}
else if (quant.MinOccurrences == 1 && quant.MaxOccurrences == 1)
{
return(quant.ChildPattern);
}
else
{
return(quant);
}
}
private Parser <char, string> createParser(BasePattern pattern)
{
if (pattern == null)
{
throw new ArgumentNullException("pattern.", "Pattern is null when creating match parser.");
}
switch (pattern.Type)
{
case PatternType.Group:
return(from vs in
CharParsers.Sequence(((GroupPattern)pattern).Patterns
.Select(p => createParser(p)))
select vs.JoinStrings());
case PatternType.Quantifier:
QuantifierPattern quant = (QuantifierPattern)pattern;
return(from vs in CharParsers.Count(quant.MinOccurrences,
quant.MaxOccurrences,
createParser(quant.ChildPattern))
select vs.JoinStrings());
case PatternType.Alternation:
return(CharParsers.Choice(((AlternationPattern)pattern).Alternatives
.Select(p => createParser(p))
.ToArray()));
case PatternType.String:
return(CharParsers.String(((StringPattern)pattern).Value));
case PatternType.Char:
return(from c in CharParsers.Satisfy(((CharPattern)pattern).IsMatch)
select new string(c, 1));
default:
throw new ApplicationException(
string.Format("ExplicitDFAMatcher: unrecognized pattern type ({0}).",
pattern.GetType().Name));
}
}
public override BasePattern Transform(BasePattern pattern)
{
if (pattern.Type == PatternType.Quantifier)
{
QuantifierPattern quant = (QuantifierPattern)pattern;
BasePattern transformedChild = Transform(quant.ChildPattern);
if (IsEmpty(transformedChild))
{
return(GroupPattern.Empty);
}
BasePattern[] newPatterns = new[]
{
new QuantifierPattern(transformedChild,
quant.MinOccurrences,
quant.MinOccurrences,
quant.IsGreedy),
new QuantifierPattern(transformedChild,
0,
quant.MaxOccurrences != null ? quant.MaxOccurrences - quant.MinOccurrences : null,
quant.IsGreedy),
}
.Select(q => reduceQuantifier(q))
.Where(IsNotEmpty)
.ToArray();
if (newPatterns.Length == 1)
{
return(newPatterns[0]);
}
else
{
return(new GroupPattern(false, newPatterns));
}
}
else
{
return(base.Transform(pattern));
}
}
public virtual BasePattern Transform(BasePattern pattern)
{
// The Identity transform
switch (pattern.Type)
{
case PatternType.Group:
GroupPattern group = (GroupPattern)pattern;
BasePattern[] newChildren = group.Patterns
.Select(p => Transform(p))
.Where(IsNotEmpty)
.ToArray();
return(CreateGroupOrSingleton(group.IsCapturing, newChildren));
case PatternType.Quantifier:
QuantifierPattern quant = (QuantifierPattern)pattern;
BasePattern newChild = Transform(quant.ChildPattern);
if (IsNotEmpty(newChild))
{
return(new QuantifierPattern(newChild, quant.MinOccurrences, quant.MaxOccurrences, quant.IsGreedy));
}
else
{
return(GroupPattern.Empty);
}
case PatternType.Alternation:
return(new AlternationPattern(((AlternationPattern)pattern).Alternatives
.Select(a => Transform(a))));
default:
return(pattern);
}
}
public QuantifierStackFrame(StackFrame parent, QuantifierPattern quant)
: this(parent, new RepeaterConsList<BasePattern>(quant.ChildPattern, quant.MaxOccurrences), quant.IsGreedy, -1)
{
if (quant.MinOccurrences != 0)
quant.AssertCanonicalForm();
}
