internal bool IsNext(Token.TokenType type)
{
return(_lookahead.IsToken(type));
}
internal bool Advance()
{
if (_errorState)
{
return(false);
}
if (_lookahead?.IsToken(Token.TokenType.EndOfInput) == true)
{
return(true);
}
SkipWhiteSpace();
// Update error position after skipping whitespace
_errorPosition = _parsePoint + 1;
if (_parsePoint >= _expression.Length)
{
_lookahead = Token.EndOfInput;
}
else
{
switch (_expression[_parsePoint])
{
case ',':
_lookahead = Token.Comma;
_parsePoint++;
break;
case '(':
_lookahead = Token.LeftParenthesis;
_parsePoint++;
break;
case ')':
_lookahead = Token.RightParenthesis;
_parsePoint++;
break;
case '$':
if (!ParseProperty())
{
return(false);
}
break;
case '%':
if (!ParseItemMetadata())
{
return(false);
}
break;
case '@':
int start = _parsePoint;
// If the caller specified that he DOESN'T want to allow item lists ...
if ((_options & ParserOptions.AllowItemLists) == 0)
{
if ((_parsePoint + 1) < _expression.Length && _expression[_parsePoint + 1] == '(')
{
_errorPosition = start + 1;
_errorState = true;
_errorResource = "ItemListNotAllowedInThisConditional";
return(false);
}
}
if (!ParseItemList())
{
return(false);
}
break;
case '!':
// negation and not-equal
if ((_parsePoint + 1) < _expression.Length && _expression[_parsePoint + 1] == '=')
{
_lookahead = Token.NotEqualTo;
_parsePoint += 2;
}
else
{
_lookahead = Token.Not;
_parsePoint++;
}
break;
case '>':
// gt and gte
if ((_parsePoint + 1) < _expression.Length && _expression[_parsePoint + 1] == '=')
{
_lookahead = Token.GreaterThanOrEqualTo;
_parsePoint += 2;
}
else
{
_lookahead = Token.GreaterThan;
_parsePoint++;
}
break;
case '<':
// lt and lte
if ((_parsePoint + 1) < _expression.Length && _expression[_parsePoint + 1] == '=')
{
_lookahead = Token.LessThanOrEqualTo;
_parsePoint += 2;
}
else
{
_lookahead = Token.LessThan;
_parsePoint++;
}
break;
case '=':
if ((_parsePoint + 1) < _expression.Length && _expression[_parsePoint + 1] == '=')
{
_lookahead = Token.EqualTo;
_parsePoint += 2;
}
else
{
_errorPosition = _parsePoint + 2; // expression[parsePoint + 1], counting from 1
_errorResource = "IllFormedEqualsInCondition";
if ((_parsePoint + 1) < _expression.Length)
{
// store the char we found instead
_unexpectedlyFound = Convert.ToString(_expression[_parsePoint + 1], CultureInfo.InvariantCulture);
}
else
{
_unexpectedlyFound = EndOfInput;
}
_parsePoint++;
_errorState = true;
return(false);
}
break;
case '\'':
if (!ParseQuotedString())
{
return(false);
}
break;
default:
// Simple strings, function calls, decimal numbers, hex numbers
if (!ParseRemaining())
{
return(false);
}
break;
}
}
return(true);
}
