50g System RPL list processing

[Gilles]

Hi Claudio, you must use 'ADD' and not '+' with the 48-50 series for arithmetic usages :

{ 1 2 3} 1 + gives {1 2 3 1}
{1 2 3} 1 ADD gives { 2 3 4}

It's not logical at all ( '+' and 'ADD' should be invert) but I think it was necessary for backward compatibility with the very earliest RPL calcs without parallel processing (28 and 48 SX?) and the bad choice of + for ADD at this time.

Invert '+' and 'ADD' would be logical but you break the backward compatibility.

With Gofer List :

{ } Sum gives 0
{ } Product gives 1

I dont understand your point of view about about "an empty list of reals or an empty list of strings"... From a User RPL point of view an empty list is ... an empty list. . An other choice could be to return NULL or NOVAL ?