public IParseTreeValue Evaluate(IParseTreeValue LHS, IParseTreeValue RHS, string opSymbol)
{
if (!(IsSupportedSymbol(opSymbol)))
{
throw new ArgumentException($"Unsupported operation ({opSymbol}) passed to Evaluate function");
}
if (opSymbol.Equals(LogicalOperators.NOT))
{
throw new ArgumentException($"Unary operator ({opSymbol}) passed to binary Evaluate function");
}
var opProvider = new OperatorTypesProvider((LHS.ValueType, RHS.ValueType), opSymbol);
if (opProvider.IsMismatch)
{
return(_valueFactory.CreateMismatchExpression($"{LHS.Token} {opSymbol} {RHS.Token}", Tokens.Variant));
}
if (ArithmeticOperators.Includes(opSymbol))
{
return(EvaluateArithmeticOp(opSymbol, LHS, RHS));
}
if (RelationalOperators.Includes(opSymbol))
{
return(EvaluateRelationalOp(opSymbol, LHS, RHS));
}
return(EvaluateLogicalOperator(opSymbol, LHS, RHS));
}
private bool IsSupportedSymbol(string opSymbol)
{
return(ArithmeticOperators.Includes(opSymbol) ||
RelationalOperators.Includes(opSymbol) ||
LogicalOperators.Incudes(opSymbol));
}
private IParseTreeValue EvaluateArithmeticOp(string opSymbol, IParseTreeValue LHS, IParseTreeValue RHS)
{
Debug.Assert(ArithmeticOperators.Includes(opSymbol));
var opProvider = new OperatorTypesProvider((LHS.ValueType, RHS.ValueType), opSymbol);
if (!(LHS.ParsesToConstantValue && RHS.ParsesToConstantValue))
{
//Unable to resolve to a value, return an expression
return(_valueFactory.CreateExpression($"{LHS.Token} {opSymbol} {RHS.Token}", opProvider.OperatorDeclaredType));
}
if (!LHS.TryLetCoerce(opProvider.OperatorEffectiveType, out var effLHS) ||
!RHS.TryLetCoerce(opProvider.OperatorEffectiveType, out var effRHS))
{
return(_valueFactory.CreateExpression($"{LHS.Token} {opSymbol} {RHS.Token}", opProvider.OperatorDeclaredType));
}
if (opProvider.OperatorEffectiveType.Equals(Tokens.Date))
{
if (!(LHS.TryLetCoerce(Tokens.Double, out effLHS) && RHS.TryLetCoerce(Tokens.Double, out effRHS)))
{
return(_valueFactory.CreateExpression($"{LHS.Token} {opSymbol} {RHS.Token}", opProvider.OperatorEffectiveType));
}
}
if (opSymbol.Equals(ArithmeticOperators.MULTIPLY))
{
return(_valueFactory.CreateValueType(Calculate(effLHS, effRHS, (decimal a, decimal b) => a * b, (double a, double b) => a * b), opProvider.OperatorDeclaredType));
}
if (opSymbol.Equals(ArithmeticOperators.DIVIDE))
{
return(_valueFactory.CreateValueType(Calculate(effLHS, effRHS, (decimal a, decimal b) => a / b, (double a, double b) => a / b), opProvider.OperatorDeclaredType));
}
if (opSymbol.Equals(ArithmeticOperators.INTEGER_DIVIDE))
{
return(_valueFactory.CreateValueType(Calculate(effLHS, effRHS, IntDivision, IntDivision), opProvider.OperatorDeclaredType));
}
if (opSymbol.Equals(ArithmeticOperators.PLUS))
{
if (opProvider.OperatorEffectiveType.Equals(Tokens.String))
{
return(_valueFactory.CreateValueType(Concatenate(LHS, RHS), opProvider.OperatorDeclaredType));
}
if (opProvider.OperatorEffectiveType.Equals(Tokens.Date))
{
var result = _valueFactory.CreateDeclaredType(Calculate(effLHS, effRHS, null, (double a, double b) => a + b), Tokens.Double);
return(_valueFactory.CreateDate(result.AsDouble()));
}
return(_valueFactory.CreateValueType(Calculate(effLHS, effRHS, (decimal a, decimal b) => a + b, (double a, double b) => a + b), opProvider.OperatorDeclaredType));
}
if (opSymbol.Equals(ArithmeticOperators.MINUS))
{
if (LHS.ValueType.Equals(Tokens.Date) && RHS.ValueType.Equals(Tokens.Date))
{
return(_valueFactory.CreateDate(LHS.AsDouble() - RHS.AsDouble()));
}
return(_valueFactory.CreateValueType(Calculate(effLHS, effRHS, (decimal a, decimal b) => a - b, (double a, double b) => a - b), opProvider.OperatorDeclaredType));
}
if (opSymbol.Equals(ArithmeticOperators.EXPONENT))
{
//Math.Pow only takes doubles, so the decimal conversion option is null
return(_valueFactory.CreateValueType(Calculate(effLHS, effRHS, null, Math.Pow), opProvider.OperatorDeclaredType));
}
if (opSymbol.Equals(ArithmeticOperators.MODULO))
{
return(_valueFactory.CreateValueType(Calculate(effLHS, effRHS, (decimal a, decimal b) => a % b, (double a, double b) => a % b), opProvider.OperatorDeclaredType));
}
//ArithmeticOperators.AMPERSAND
return(_valueFactory.CreateValueType(Concatenate(LHS, RHS), opProvider.OperatorDeclaredType));
}