functional programming

[eddier]

It would be nice if the procedures push, remove, replace, etc, were functions that is,  returned their  results like sort and returned the info they now return through their name as a system variable.



Example

Code Select Expand


(set 'aList '(a b c d e a b c d))
(replace 'b aList 'B)              => (a B c d e a B c d)
$$ => 2


Making everything a function would cut down on those (begin thingys. And allow functional composition of  push, remove, replace, etc, with other functions.



Eddie

[Lutz]

When those functions 'replace', 'replace-nth' and 'replace-assoc' where written I had in mind to save memory when using these on big in memory datatbases.



'sort' and 'reverse' then where written not this way and return the result working in a functional way, which of course was inconsistent with the replace family of functions.



Perhaps the best would be having them all return their result and making them non-destructive, so only the functions having to change the contents of a symbol would be destructive.



The only problem I have, is, that it would break a lot of code out there. But it clearly would be more consistent and save some sequential no-functional code.



I personally would agree to this change making them all non-destrutive with functional returns, but I don't know how others (beside you) think about it?



Perhaps announcing it a couple versions early and then doing it in 8.0?



What does everybody else think?



Lutz

[HPW]

For me it would be not a problem, because I just start to port larger

sources to newLisp. I only had to know early where it goes. Of cource

consistents sounds always good.



But others will have more to change.



Just my 2 cents.

[eddier]

Thanks Lutz for the changes in 7.2.4.  Now I can kill the library with functional versions of replace, remove, etc...



Eddie

[Lutz]

thanks for making the suggestions to change those functions in the first place ;) .  I left push the way it is, to have at least one pair of destructive primitives (push, pop) to modify big in-memory lists without allocating memory for a copy of the list.



Also when push is used without the offset parameter, you can just use 'cons' which does returns the modified list.



Lutz