private SubExpression And()
{
SubExpression expr = Or();
while (Peek != null)
{
expr = new AndExpression(new List <SubExpression> {
expr, Or()
});
}
return(expr);
}
private SubExpression Factor()
{
Token peek = Peek;
if (Peek is WordToken word)
{
SubExpression sub = null;
foreach (char c in word.Lexeme)
{
if (sub == null)
{
sub = new SingleCharacterExpression(c);
}
else
{
sub = new AndExpression(new List <SubExpression> {
sub, new SingleCharacterExpression(c)
});
}
}
Next();
return(sub);
}
else if (peek.Character == '(')
{
Next();
SubExpression sub = Or();
Next(')');
return(sub);
}
else if (peek.Character == '[')
{
Next();
WordToken token = ((WordToken)Peek);
char rangeStart = '\0';
List <char> unionedRange = new List <char>();
foreach (char c in token.Lexeme)
{
if (rangeStart == '\0')
{
rangeStart = c;
}
else if (c != '-')
{
List <char> range = Ranges.First(x => x.Contains(rangeStart) && x.Contains(c));
for (int i = range.IndexOf(rangeStart); i < range.IndexOf(c) + 1; i++)
{
unionedRange.Add(range[i]);
}
rangeStart = '\0';
}
}
Next();
Next(']');
List <SubExpression> subExpressions = new List <SubExpression>();
foreach (char c in unionedRange)
{
subExpressions.Add(new SingleCharacterExpression(c));
}
return(new OrExpression(subExpressions));
}
else
{
SubExpression sub = new SingleCharacterExpression(peek.Character);
Next();
return(sub);
}
}
