Re: [Caml-list] Clarification for the configuration of comparison functions

[Gerd Stolpmann <info@gerd-stolpmann.de>]

[-- Attachment #1: Type: text/plain, Size: 1503 bytes --]

Am Mittwoch, den 10.09.2014, 10:56 +0200 schrieb SF Markus Elfring:
> Hello,
> 
> I extended my software development experience a bit for the programming language
> "OCaml". I find my knowledge incomplete here to resolve an issue like
> "Comparison function application" alone.
> https://github.com/elfring/OTCL/issues/4

There are three reasons why you want to have your own comparison
function:

- You need a different ordering than provided by Pervasives.compare.
  For compound types the ordering of compare is implementation-defined,
  and currently the implementation prefers the fastest way of comparing.
  E.g. if you compare arrays, you don't get a lexicographic ordering.
  This is sometimes not what you need.
- Your values are cyclic. compare may hang if you try to compare cyclic
  values.
- Your values contains parts that cannot be compared, like functions.
  With a custom comparison function you can skip these parts.

Gerd

> How do you think about to discuss corresponding implementation details for an
> evolving class library?
> 
> I would appreciate your advices.
> 
> Regards,
> Markus
> 

-- 
------------------------------------------------------------
Gerd Stolpmann, Darmstadt, Germany    gerd@gerd-stolpmann.de
My OCaml site:          http://www.camlcity.org
Contact details:        http://www.camlcity.org/contact.html
Company homepage:       http://www.gerd-stolpmann.de
------------------------------------------------------------


[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 473 bytes --]