private RegexTerm VisitRegexTermNode(IInternalTreeNode internalNode)
{
RegexFactor factor = null;
RegexTerm term = null;
for (var c = 0; c < internalNode.Children.Count; c++)
{
var child = internalNode.Children[c];
if (child.NodeType != TreeNodeType.Internal)
{
continue;
}
var childInternalNode = child as IInternalTreeNode;
var childInternalNodeSymbolValue = childInternalNode.Symbol.Value;
if (RegexGrammar.Factor == childInternalNodeSymbolValue)
{
factor = VisitRegexFactorNode(childInternalNode);
}
else if (RegexGrammar.Term == childInternalNodeSymbolValue)
{
term = VisitRegexTermNode(childInternalNode);
}
}
if (term == null)
{
return(new RegexTerm(factor));
}
return(new RegexTermFactor(factor, term));
}
private static INfa Term(RegexTerm term)
{
switch (term.NodeType)
{
case RegexNodeType.RegexTerm:
return(Factor(term.Factor));
case RegexNodeType.RegexTermFactor:
var regexTermFactor = term as RegexTermFactor;
var factorNfa = Factor(regexTermFactor.Factor);
var termNfa = Term(regexTermFactor.Term);
return(Concatenation(factorNfa, termNfa));
}
throw new InvalidOperationException("Unrecognized Regex Term");
}
private RegexExpression VisitRegexExpressionNode(IInternalTreeNode internalNode)
{
RegexExpression expression = null;
RegexTerm term = null;
for (var c = 0; c < internalNode.Children.Count; c++)
{
var child = internalNode.Children[c];
if (child.NodeType != TreeNodeType.Internal)
{
continue;
}
var childInternalNode = child as IInternalTreeNode;
var childInternalNodeSymbolValue = childInternalNode.Symbol.Value;
if (RegexGrammar.Expression == childInternalNodeSymbolValue)
{
expression = VisitRegexExpressionNode(childInternalNode);
}
else if (RegexGrammar.Term == childInternalNodeSymbolValue)
{
term = VisitRegexTermNode(childInternalNode);
}
}
if (expression != null && term != null)
{
return(new RegexExpressionAlteration(term, expression));
}
if (term != null)
{
return(new RegexExpressionTerm(term));
}
throw new InvalidOperationException("Unable to create null expression.");
}
public RegexExpressionAlteration(RegexTerm term, RegexExpression expression)
: base(term)
{
Expression = expression;
_hashCode = ComputeHashCode();
}
public RegexExpressionTerm(RegexTerm term)
{
Term = term;
_hashCode = ComputeHashCode();
}
public RegexTermFactor(RegexFactor factor, RegexTerm term)
: base(factor)
{
Term = term;
_hashCode = ComputeHashCode();
}
public RegexTermFactor(RegexFactor factor, RegexTerm term)
: base(factor)
{
Term = term;
_hashCode = ComputeHashCode();
}
public RegexExpressionAlteration(RegexTerm term, RegexExpression expression)
: base(term)
{
Expression = expression;
_hashCode = ComputeHashCode();
}
public RegexExpressionTerm(RegexTerm term)
{
Term = term;
_hashCode = ComputeHashCode();
}
private static INfa Term(RegexTerm term)
{
switch (term.NodeType)
{
case RegexNodeType.RegexTerm:
return Factor(term.Factor);
case RegexNodeType.RegexTermFactor:
var regexTermFactor = term as RegexTermFactor;
var factorNfa = Factor(regexTermFactor.Factor);
var termNfa = Term(regexTermFactor.Term);
return Concatenation(factorNfa, termNfa);
}
throw new InvalidOperationException("Unrecognized Regex Term");
}
