public static RegexExpression CreateString(string value)
{
if (string.IsNullOrEmpty(value))
{
return(null);
}
RegexExpression result = new RegexLiteralExpression(value[0]);
for (var i = 1; i < value.Length; i++)
{
result = new RegexConcatExpression(result, new RegexLiteralExpression(value[i]));
}
return(result);
}
internal static RegexExpression Parse(ParseContext pc)
{
RegexExpression result = null, next = null;
int ich;
pc.EnsureStarted();
var line = pc.Line;
var column = pc.Column;
var position = pc.Position;
while (true)
{
switch (pc.Current)
{
case -1:
return(result);
case '.':
var nset = new RegexCharsetExpression(new RegexCharsetEntry[] { new RegexCharsetRangeEntry(char.MinValue, char.MaxValue) }, false);
nset.SetLocation(line, column, position);
if (null == result)
{
result = nset;
}
else
{
result = new RegexConcatExpression(result, nset);
result.SetLocation(line, column, position);
}
pc.Advance();
result = _ParseModifier(result, pc);
line = pc.Line;
column = pc.Column;
position = pc.Position;
break;
case '\\':
if (-1 != (ich = _ParseEscape(pc)))
{
next = new RegexLiteralExpression((char)ich);
next.SetLocation(line, column, position);
next = _ParseModifier(next, pc);
if (null != result)
{
result = new RegexConcatExpression(result, next);
result.SetLocation(line, column, position);
}
else
{
result = next;
}
}
else
{
pc.Expecting(); // throw an error
return(null); // doesn't execute
}
line = pc.Line;
column = pc.Column;
position = pc.Position;
break;
case ')':
return(result);
case '(':
pc.Advance();
pc.Expecting();
next = Parse(pc);
pc.Expecting(')');
pc.Advance();
next = _ParseModifier(next, pc);
if (null == result)
{
result = next;
}
else
{
result = new RegexConcatExpression(result, next);
result.SetLocation(line, column, position);
}
line = pc.Line;
column = pc.Column;
position = pc.Position;
break;
case '|':
if (-1 != pc.Advance())
{
next = Parse(pc);
result = new RegexOrExpression(result, next);
result.SetLocation(line, column, position);
}
else
{
result = new RegexOrExpression(result, null);
result.SetLocation(line, column, position);
}
line = pc.Line;
column = pc.Column;
position = pc.Position;
break;
case '[':
pc.ClearCapture();
pc.Advance();
pc.Expecting();
bool not = false;
if ('^' == pc.Current)
{
not = true;
pc.Advance();
pc.Expecting();
}
var ranges = _ParseRanges(pc);
if (ranges.Count == 0)
{
System.Diagnostics.Debugger.Break();
}
pc.Expecting(']');
pc.Advance();
next = new RegexCharsetExpression(ranges, not);
next.SetLocation(line, column, position);
next = _ParseModifier(next, pc);
if (null == result)
{
result = next;
}
else
{
result = new RegexConcatExpression(result, next);
result.SetLocation(pc.Line, pc.Column, pc.Position);
}
line = pc.Line;
column = pc.Column;
position = pc.Position;
break;
default:
ich = pc.Current;
next = new RegexLiteralExpression((char)ich);
next.SetLocation(line, column, position);
pc.Advance();
next = _ParseModifier(next, pc);
if (null == result)
{
result = next;
}
else
{
result = new RegexConcatExpression(result, next);
result.SetLocation(line, column, position);
}
line = pc.Line;
column = pc.Column;
position = pc.Position;
break;
}
}
}
