/// <summary>
/// Initialize a new instance of <see cref="ProgramInterpreter"/>
/// </summary>
/// <param name="programDeclaration">the program declaration</param>
/// <param name="debugMode">Defines if the debug mode is enabled</param>
internal ProgramInterpreter(AlgorithmProgram programDeclaration, bool debugMode)
: base(debugMode)
{
ProgramDeclaration = programDeclaration;
// Just for better performances after, we call it a first time
OperatorHelperCache.Initialize();
}
/// <summary>
/// Run the interpretation
/// </summary>
/// <returns>Returns the result of the interpretation</returns>
internal override object Execute()
{
object left;
object right;
MethodInfo operatorMethod;
left = ParentInterpreter.RunExpression(Expression._leftExpression);
if (ParentInterpreter.FailedOrStop)
{
return(null);
}
right = ParentInterpreter.RunExpression(Expression._rightExpression);
if (ParentInterpreter.FailedOrStop)
{
return(null);
}
if (DebugMode)
{
ParentInterpreter.Log(this, $"Doing an operation '{Expression._operator}'");
}
if (Expression._operator == AlgorithmBinaryOperatorType.Equals)
{
if (left == null)
{
if (right == null)
{
return(true); // null == null
}
return(right.Equals(null));
}
return(left.Equals(right));
}
operatorMethod = OperatorHelperCache.GetOperator(Expression._operator, left.GetType(), right.GetType());
if (operatorMethod == null)
{
ParentInterpreter.ChangeState(this, new AlgorithmInterpreterStateEventArgs(new Error(new OperatorNotFoundException(Expression._operator.ToString(), $"Operator '{Expression._operator}' cannot be applied to operands of type '{left.GetType().FullName}' and '{right.GetType().FullName}'"), Expression), ParentInterpreter.GetDebugInfo()));
return(null);
}
if (Expression._operator == AlgorithmBinaryOperatorType.Division)
{
long num;
var convertedToLong = long.TryParse(right.ToString(), out num);
if (convertedToLong && num == 0)
{
ParentInterpreter.ChangeState(this, new AlgorithmInterpreterStateEventArgs(new Error(new DivideByZeroException("Attempted to divide by zero."), Expression), ParentInterpreter.GetDebugInfo()));
return(null);
}
}
return(operatorMethod.Invoke(null, new[] { left, right }));
}
