public override Expression Scan(ParseEngine engine)
{
var chars = engine.Characters;
var start = engine.Pointer;
if (chars[start] == '"' || (chars[start] == '@' && start + 1 < chars.Length && chars[start + 1] == '"'))
{
var index = start;
var exp = new StringExpression(engine);
var escape = false;
var terminated = false;
var sb = new StringBuilder();
if (chars[index] == '@')
{
index += 2;
exp.literal = true;
}
else
{
index++;
}
while (index < chars.Length)
{
if (!literal && !escape && chars[index] == '\\')
{
escape = true;
}
else if (!escape && chars[index] == '"')
{
terminated = true;
index++;
break;
}
else if (escape)
{
switch (chars[index])
{
case 't':
sb.Append("\t");
break;
case 'n':
sb.AppendLine();
break;
case '\\':
case '"':
sb.Append(chars[index]);
break;
default:
engine.SetPointer(index);
engine.AddError(new YAMPEscapeSequenceNotFoundError(engine, chars[index]), exp);
break;
}
escape = false;
}
else
{
sb.Append(chars[index]);
}
index++;
}
if (!terminated)
{
engine.AddError(new YAMPStringNotTerminatedError(engine), exp);
}
exp.value = sb.ToString();
exp.Length = index - start;
engine.SetPointer(index);
return exp;
}
return null;
}
