/// <summary>
/// Attempts to find a TNumber value for the TType given. If there is no error, but the TNumber reference
/// given is still null after calling, then the TType is a TString (i.e. some arithmetic will work (+)).
/// </summary>
/// <param name="interpreter">The interpreter that the method is being called from.</param>
/// <param name="number">The TNumber reference to assign the result to.</param>
/// <param name="value">The TType to get a TNumber out of.</param>
/// <returns>An exception if there was an error, otherwise null.</returns>
private static TException AssignNumberValue(Interpreter interpreter, out TNumber number, TType value)
{
// Attempt to cast the TType 'value' argument to a TNumber. Failing that, check if it's a TString.
// If the value is a TNumber or a TString, return null (i.e. no exception). If it's a TVariable then
// work on the value of the TVariable, otherwise return an exception.
number = value as TNumber;
if ((number != null) || (value is TString)) return null;
TVariable variable = value as TVariable;
if (variable != null)
{
value = variable.Value;
number = value as TNumber;
if ((number != null) || (value is TString)) return null;
return new TException(interpreter, "Value of '" + variable.Identifier + "' is not a number",
"it is of type '" + value.TypeName + "'");
}
return new TException(interpreter, "'" + value.ToCSString() + "' is not a number",
"it is of type '" + value.TypeName + "'");
}