private SyntaxTreeNode GetNode(SubExpression expression)
{
if (expression is RepeatedExpression repeatedExpression)
{
if (repeatedExpression.RepetitionOperator == '*')
{
SyntaxTreeNode node = GetNode(repeatedExpression.Expression);
SyntaxTreeNode parent = CreateNode();
parent.Type = SyntaxTreeNodeType.Star;
node.Parent = parent;
parent.Children.Add(node);
return(parent);
}
else if (repeatedExpression.RepetitionOperator == '+')
{
SyntaxTreeNode node = GetNode(repeatedExpression.Expression);
SyntaxTreeNode parent = CreateNode();
parent.Type = SyntaxTreeNodeType.Plus;
node.Parent = parent;
parent.Children.Add(node);
return(parent);
}
}
else if (expression is OrExpression orExpression)
{
SyntaxTreeNode left = null;
SyntaxTreeNode right = null;
SyntaxTreeNode lastParent = null;
foreach (SubExpression subExpression in orExpression.SubExpressions)
{
if (left == null)
{
left = GetNode(subExpression);
continue;
}
else if (right == null)
{
right = GetNode(subExpression);
SyntaxTreeNode parent = CreateNode();
parent.Type = SyntaxTreeNodeType.Or;
left.Parent = parent;
right.Parent = parent;
parent.Children.Add(left);
parent.Children.Add(right);
lastParent = parent;
left = parent;
right = null;
}
}
return(lastParent);
}
else if (expression is AndExpression andExpression)
{
SyntaxTreeNode left = null;
SyntaxTreeNode right = null;
SyntaxTreeNode lastParent = null;
foreach (SubExpression subExpression in andExpression.SubExpressions)
{
if (left == null)
{
left = GetNode(subExpression);
continue;
}
else if (right == null)
{
right = GetNode(subExpression);
SyntaxTreeNode parent = CreateNode();
parent.Type = SyntaxTreeNodeType.And;
left.Parent = parent;
right.Parent = parent;
parent.Children.Add(left);
parent.Children.Add(right);
lastParent = parent;
left = parent;
right = null;
}
}
return(lastParent);
}
else if (expression is SingleCharacterExpression singleCharacter)
{
return(new SyntaxTreeNode {
Character = singleCharacter.Character, Type = SyntaxTreeNodeType.Leaf
});
}
return(null);
}
private SyntaxTreeNode DoConvert(string regex)
{
SubExpression subExpression = RegexToSubExpressionConverter.Convert(regex);
return(GetNode(subExpression));
}