protected ComparisonNode ParseComparison(Lexer lexer)
{
var lft = ParseSumCalculation(lexer);
SkipWhiteSpace(lexer);
Match m = Regex.Match(lexer.Peek(2), "==|!=|<=|>=|<|>");
string comp = null;
SumCalculationNode rgt = null;
if (m.Success)
{
comp = m.Groups[0].Value;
lexer.Consume();
if (comp.Length == 2)
{
lexer.Consume();
}
SkipWhiteSpace(lexer);
rgt = ParseSumCalculation(lexer);
}
return(new ComparisonNode()
{
lft = lft,
comp = comp,
rgt = rgt,
});
}
private object EvaluateNode(SumCalculationNode expression, Context context)
{
var lft = EvaluateNode(expression.lft, context);
var value = lft;
if (expression.args == null || expression.args.Length == 0)
{
return(value);
}
float floatVal = 0;
var isConcatenation = (value is string) || !float.TryParse(value.ToString(), out floatVal);
foreach (var term in expression.args)
{
float floatRgt = 0;
var rgt = EvaluateNode(term.rgt, context).ToString();
if (!isConcatenation)
{
isConcatenation = !float.TryParse(rgt, out floatRgt);
}
switch (term.op)
{
case "+":
if (isConcatenation)
{
value = (string)value + rgt.ToString();
isConcatenation = true;
}
else
{
floatVal += floatRgt;
}
break;
case "-":
if (isConcatenation)
{
value = string.Empty;
}
else
{
floatVal -= floatRgt;
}
break;
}
}
return(isConcatenation ? value : floatVal);
}
protected ComparisonNode ParseComparison()
{
var lft = ParseSumCalculation();
string comparisonOperator = null;
switch (PeekToken().Type)
{
case TokenType.OP_EQUAL:
comparisonOperator = "==";
break;
case TokenType.OP_NOTEQUAL:
comparisonOperator = "!=";
break;
case TokenType.OP_LESS:
comparisonOperator = "<";
break;
case TokenType.OP_LESSEQUAL:
comparisonOperator = "<=";
break;
case TokenType.OP_GREATER:
comparisonOperator = ">";
break;
case TokenType.OP_GREATEREQUAL:
comparisonOperator = ">=";
break;
}
SumCalculationNode rgt = null;
if (comparisonOperator != null)
{
NextToken();
rgt = ParseSumCalculation();
}
return(new ComparisonNode()
{
lft = lft,
comp = comparisonOperator,
rgt = rgt,
});
}
