private void ParseIdentifier()
{
string identifier = string.Empty;
int positionStart = currentPosition;
while (CurrentChar == '_' || char.IsLetterOrDigit(CurrentChar))
{
identifier += CurrentChar;
NextChar();
}
switch (identifier)
{
case "AND":
expressionTokens.Add(new OperatorToken(TokenType.AndOperator, positionStart));
NextToken();
break;
case "OR":
expressionTokens.Add(new OperatorToken(TokenType.OrOperator, positionStart));
NextToken();
break;
case "NOT":
expressionTokens.Add(new OperatorToken(TokenType.NotOperator, positionStart));
NextToken();
break;
case "TRUE":
case "FALSE":
ValueToken booleanToken = new ValueToken
{
Type = TokenType.BooleanValue,
StringValue = identifier,
SystemValue = (identifier == "TRUE"),
PositionStart = positionStart
};
expressionTokens.Add(booleanToken);
NextToken();
break;
case "LOE":
expressionTokens.Add(new OperatorToken(TokenType.LessOrEqualOperator, positionStart));
NextToken();
break;
case "GOE":
expressionTokens.Add(new OperatorToken(TokenType.GreaterOrEqualOperator, positionStart));
NextToken();
break;
default:
ExpressionToken identifierToken = new ExpressionToken();
identifierToken.StringValue = identifier;
identifierToken.Type = TokenType.Identifier;
identifierToken.PositionStart = positionStart;
expressionTokens.Add(identifierToken);
NextToken();
break;
}
}
private void ParseNumber()
{
string stringNumber = String.Empty;
ValueToken currentToken = new ValueToken
{
PositionStart = currentPosition,
Type = TokenType.IntegerValue
};
while (char.IsDigit(CurrentChar))
{
stringNumber += CurrentChar;
NextChar();
}
if (CurrentChar == '.')
{
currentToken.Type = TokenType.DecimalValue;
stringNumber += CurrentChar;
NextChar();
if (!char.IsDigit(CurrentChar))
{
throw new ArgumentException($"Unexpected '{CurrentChar}' at position {currentPosition}.\nDigit was expected.");
}
while (char.IsDigit(CurrentChar))
{
stringNumber += CurrentChar;
NextChar();
}
}
currentToken.SystemValue = stringNumber;
expressionTokens.Add(currentToken);
NextToken();
}
public void ParseString()
{
ValueToken currentToken = new ValueToken
{
PositionStart = currentPosition,
Type = TokenType.StringValue
};
NextChar();
string stringValue = String.Empty;
while (!(CurrentChar == '\'' || CurrentChar == '\0'))
{
stringValue += CurrentChar;
NextChar();
}
if (CurrentChar == '\0')
{
throw new ArgumentException("String value must be enclosed by ' character!");
}
currentToken.SystemValue = stringValue;
expressionTokens.Add(currentToken);
NextChar();
NextToken();
}