static RegexExpression _ParseModifier(RegexExpression expr, ParseContext pc)
{
var line = pc.Line;
var column = pc.Column;
var position = pc.Position;
switch (pc.Current)
{
case '*':
expr = new RegexRepeatExpression(expr);
expr.SetLocation(line, column, position);
pc.Advance();
break;
case '+':
expr = new RegexRepeatExpression(expr, 1);
expr.SetLocation(line, column, position);
pc.Advance();
break;
case '?':
expr = new RegexOptionalExpression(expr);
expr.SetLocation(line, column, position);
pc.Advance();
break;
case '{':
pc.Advance();
pc.TrySkipWhiteSpace();
pc.Expecting('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', ',', '}');
var min = -1;
var max = -1;
if (',' != pc.Current && '}' != pc.Current)
{
var l = pc.CaptureBuffer.Length;
pc.TryReadDigits();
min = int.Parse(pc.GetCapture(l));
pc.TrySkipWhiteSpace();
}
if (',' == pc.Current)
{
pc.Advance();
pc.TrySkipWhiteSpace();
pc.Expecting('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '}');
if ('}' != pc.Current)
{
var l = pc.CaptureBuffer.Length;
pc.TryReadDigits();
max = int.Parse(pc.GetCapture(l));
pc.TrySkipWhiteSpace();
}
}
else
{
max = min;
}
pc.Expecting('}');
pc.Advance();
expr = new RegexRepeatExpression(expr, min, max);
expr.SetLocation(line, column, position);
break;
}
return(expr);
}
