public virtual IntervalSet GetSetFromCharSetLiteral(GrammarAST charSetAST)
{
string chars = charSetAST.Text;
chars = chars.Substring(1, chars.Length - 2);
string cset = '"' + chars + '"';
IntervalSet set = new IntervalSet();
if (chars.Length == 0)
{
g.tool.errMgr.GrammarError(ErrorType.EMPTY_STRINGS_AND_SETS_NOT_ALLOWED,
g.fileName, charSetAST.Token, "[]");
return set;
}
// unescape all valid escape char like \n, leaving escaped dashes as '\-'
// so we can avoid seeing them as '-' range ops.
chars = CharSupport.GetStringFromGrammarStringLiteral(cset);
if (chars == null)
{
g.tool.errMgr.GrammarError(ErrorType.INVALID_ESCAPE_SEQUENCE,
g.fileName, charSetAST.Token);
return set;
}
int n = chars.Length;
// now make x-y become set of char
for (int i = 0; i < n; i++)
{
int c = chars[i];
if (c == '\\' && (i + 1) < n && chars[i + 1] == '-')
{ // \-
CheckSetCollision(charSetAST, set, '-');
set.Add('-');
i++;
}
else if ((i + 2) < n && chars[i + 1] == '-')
{ // range x-y
int x = c;
int y = chars[i + 2];
if (x <= y)
{
CheckSetCollision(charSetAST, set, x, y);
set.Add(x, y);
}
else
{
g.tool.errMgr.GrammarError(ErrorType.EMPTY_STRINGS_AND_SETS_NOT_ALLOWED,
g.fileName, charSetAST.Token, "[" + (char)x + "-" + (char)y + "]");
}
i += 2;
}
else
{
CheckSetCollision(charSetAST, set, c);
set.Add(c);
}
}
return set;
}
