> < ^ Date: Tue, 16 Feb 1993 10:33:35 +0100
> < ^ From: Jean Michel <jmichel@math.jussieu.fr >
^ Subject: Re: apologies

>> Such request as shown by the problems that you mention in your first
>> letter is certainly reasonable and ought to be discussed if problems
>> of the commodity of using GAP have arisen as it has been the case with
>> you. I do not think, however, that such a request is a reason to use
>> in a public worldwide discussion terms like you have chosen in your
>> letters, like talking of "a wrong treatment of empties" or "an
>> unnecessary confused answer" and the like. While we are grateful for
>> each notification of a real bug, and while we appreciate every
>> suggestion for the improvement of GAP, I am not willing to accept that
>> users of GAP use a tone in the discussion with us like an impatient
>> teacher may (but should not) use with a dumb student.
>>
I wish to apologize for the tone of my replies. I tend to write as I
speak in the heat of the discussion, and always forget that the written
word does not carry any of the verbal and gestual clues which put things
in the proper context. But, please, do not think this reflect an
inferior opinion of your ideas, on the contrary, I only become excited
when discussing exciting topics (and never ever when I speak with
someone dumb).

P.S. I also think now from your reply that my question has been fully
understood, so I wait eagerly for what you will do.

Now another small tought about GAP to make this letter a better fit for
the forum:

I have had often to write code, like: 'find all rows of a matrix where an
entry is the single non-zero in its column' where it would be very
useful to interpret boolean true as 1 and boolean false as 0, like in C:
then this particular code could be:

Filtered(mat,List(Sum(mat,x->x<>0),y->y=1));

Actually implicit conversion is not necessary, it would be just
as good to write

Filtered(mat,List(Sum(mat,x->Int(x<>0)),y->y=1));

if Int did the conversion job. And further, a change to GAP is
unnecessary, I can always define:

BooltoInt:=function(b) if b then return 1 else return 0 fi;end;

But, here is my problem: since GAP is yet interpreted, not compiled,
calling a user-defined function like this is very costly. So what to do:

- can this functionality be added to Int or any other function?
- will it be possible to link to GAP functions written in C?
- will there be a compiler some day?

Best regards, Jean MICHEL


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