public bool TryEvaluate(string expr, out ExpressionValue result)
{
List <Token> list = Scanner.TokenizeText(expr, _opts);
return(TryEvaluate(list, out result));
}
/// <summary>
/// Reference used for this implementation
///
/// https://gcc.gnu.org/onlinedocs/cpp/If.html#If
///
/// In summary calculations done using the widest type known to compiler which is long for
/// our implementation.
/// </summary>
public static ExpressionValue EvaluateBinaryOperation(BinaryOperator op, ExpressionValue left, ExpressionValue right)
{
long leftValue;
bool leftBool;
long rightValue;
bool rightBool;
try
{
leftValue = left.ConvertToLong();
leftBool = left.ConvertToBool();
rightValue = right.ConvertToLong();
rightBool = right.ConvertToBool();
}
catch (Exception ex)
{
throw new Exception($"Unable to convert binary operands: {ex.Message}", ex);
}
ExpressionValue result;
switch (op)
{
case BinaryOperator.Divide:
result = ExpressionValue.Create(leftValue / rightValue);
break;
case BinaryOperator.GreaterThan:
result = ExpressionValue.Create(leftValue > rightValue);
break;
case BinaryOperator.GreaterThanOrEqualTo:
result = ExpressionValue.Create(leftValue >= rightValue);
break;
case BinaryOperator.LessThan:
result = ExpressionValue.Create(leftValue < rightValue);
break;
case BinaryOperator.LessThanOrEqualTo:
result = ExpressionValue.Create(leftValue <= rightValue);
break;
case BinaryOperator.Subtract:
result = ExpressionValue.Create(leftValue - rightValue);
break;
case BinaryOperator.Modulus:
result = ExpressionValue.Create(leftValue % rightValue);
break;
case BinaryOperator.ShiftLeft:
result = ExpressionValue.Create(leftValue << (int)rightValue);
break;
case BinaryOperator.ShiftRight:
result = ExpressionValue.Create(leftValue >> (int)rightValue);
break;
case BinaryOperator.Add:
result = ExpressionValue.Create(leftValue + rightValue);
break;
case BinaryOperator.Multiply:
result = ExpressionValue.Create(leftValue * rightValue);
break;
case BinaryOperator.BooleanAnd:
result = ExpressionValue.Create(leftBool && rightBool);
break;
case BinaryOperator.BooleanOr:
result = ExpressionValue.Create(leftBool || rightBool);
break;
case BinaryOperator.BooleanEquals:
result = ExpressionValue.Create(leftValue == rightValue);
break;
case BinaryOperator.BooleanNotEquals:
result = ExpressionValue.Create(leftValue != rightValue);
break;
case BinaryOperator.BitwiseAnd:
result = ExpressionValue.Create(leftValue & rightValue);
break;
case BinaryOperator.BitwiseOr:
result = ExpressionValue.Create(leftValue | rightValue);
break;
case BinaryOperator.Assign:
result = right;
break;
default:
throw Contract.CreateInvalidEnumValueException(op);
}
return(result);
}
private ExpressionValue EvaluateNegation(ExpressionNode node)
{
var value = EvaluateCore(node.LeftNode);
return(ExpressionValue.Create(!value.ConvertToBool()));
}
