private double ScanFraction()
{
Debug.Assert(XmlCharType.IsDigit(this.CurerntChar));
int start = xpathExprIndex - 2;
Debug.Assert(0 <= start && this.xpathExpr[start] == '.');
int len = 1; // '.'
while (XmlCharType.IsDigit(this.CurerntChar))
{
NextChar(); len++;
}
return(ToXPathDouble(this.xpathExpr.Substring(start, len)));
}
private double ScanNumber()
{
Debug.Assert(this.CurerntChar == '.' || XmlCharType.IsDigit(this.CurerntChar));
int start = xpathExprIndex - 1;
int len = 0;
while (XmlCharType.IsDigit(this.CurerntChar))
{
NextChar(); len++;
}
if (this.CurerntChar == '.')
{
NextChar(); len++;
while (XmlCharType.IsDigit(this.CurerntChar))
{
NextChar(); len++;
}
}
return(ToXPathDouble(this.xpathExpr.Substring(start, len)));
}
public bool NextLex()
{
SkipSpace();
switch (this.CurerntChar)
{
case '\0':
kind = LexKind.Eof;
return(false);
case ',':
case '@':
case '(':
case ')':
case '|':
case '*':
case '[':
case ']':
case '+':
case '-':
case '=':
case '#':
case '$':
kind = (LexKind)Convert.ToInt32(this.CurerntChar);
NextChar();
break;
case '<':
kind = LexKind.Lt;
NextChar();
if (this.CurerntChar == '=')
{
kind = LexKind.Le;
NextChar();
}
break;
case '>':
kind = LexKind.Gt;
NextChar();
if (this.CurerntChar == '=')
{
kind = LexKind.Ge;
NextChar();
}
break;
case '!':
kind = LexKind.Bang;
NextChar();
if (this.CurerntChar == '=')
{
kind = LexKind.Ne;
NextChar();
}
break;
case '.':
kind = LexKind.Dot;
NextChar();
if (this.CurerntChar == '.')
{
kind = LexKind.DotDot;
NextChar();
}
else if (XmlCharType.IsDigit(this.CurerntChar))
{
kind = LexKind.Number;
numberValue = ScanFraction();
}
break;
case '/':
kind = LexKind.Slash;
NextChar();
if (this.CurerntChar == '/')
{
kind = LexKind.SlashSlash;
NextChar();
}
break;
case '"':
case '\'':
this.kind = LexKind.String;
this.stringValue = ScanString();
break;
default:
if (XmlCharType.IsDigit(this.CurerntChar))
{
kind = LexKind.Number;
numberValue = ScanNumber();
}
else if (XmlCharType.IsStartNCNameChar(this.CurerntChar))
{
kind = LexKind.Name;
this.name = ScanName();
this.prefix = string.Empty;
// "foo:bar" is one lexem not three because it doesn't allow spaces in between
// We should distinct it from "foo::" and need process "foo ::" as well
if (this.CurerntChar == ':')
{
NextChar();
// can be "foo:bar" or "foo::"
if (this.CurerntChar == ':') // "foo::"
{
NextChar();
kind = LexKind.Axe;
}
else // "foo:*", "foo:bar" or "foo: "
{
this.prefix = this.name;
if (this.CurerntChar == '*')
{
NextChar();
this.name = "*";
}
else if (XmlCharType.IsStartNCNameChar(this.CurerntChar))
{
this.name = ScanName();
}
else
{
throw new XPathException(String.Format("'{0}' has an invalid qualified name.", SourceText));
}
}
}
else
{
SkipSpace();
if (this.CurerntChar == ':')
{
NextChar();
// it can be "foo ::" or just "foo :"
if (this.CurerntChar == ':')
{
NextChar();
kind = LexKind.Axe;
}
else
{
throw new XPathException(String.Format("'{0}' has an invalid qualified name.", SourceText));
}
}
}
SkipSpace();
this.canBeFunction = (this.CurerntChar == '(');
}
else
{
throw new XPathException(String.Format("'{0}' has an invalid token.", SourceText));
}
break;
}
return(true);
}