Re: [Caml-list] Future of labels

[Judicael Courant <Judicael.Courant@lri.fr>]

Jacques Garrigue a écrit :

> Sorry for Judicael, but I see no way to satisfy everybody with a single
> mode. (You don't expect me to just drop the label mode, and be happy
> with classic, no ?)
> 

No I can't. But I did neither expect you to remove labels from the
standard library: this would be just another way to drop labels, would
not it? :-)

> On the other hand Manuel expresses an opinion I've heard a few times:
> moving to label mode might be nice, if the price to pay was not so
> high.

I agree with this statement and that's why I would have prefered a
single mode: my problem is that with two modes I cannot say "ok, I am
just giving a try to the modern  style within this function/this file"
mostly because I have to choose classic vs modern for a whole file and
even for a whole project (as I do not want my Makefile to become a
nightmare because of labels).

Unfortunately it appears there is no mode that is "better" than both the
current classic *and* modern ones. So we need two modes.
Then, I am not opposed to have labels as the default mode (classic being
kept only for backward compatibility). However I wish there would be a
way to switch to this classic mode with a pragma (not only with a
command-line switch) so that it is easier to mix files in classic mode
and in modern mode in a given project (and if it is even possible, to
mix functions written in classic modes and in modern mode within a given
file). That would help moving eventually to modern mode. IMHO "There's
More Than One Way To Do It" is not necessarily a good slogan...

If I switch to labels, I would prefer changes to happen once. If you
remove labels from the standard library and leave them in third parties
libraries, either people won't use third-parties libraries (which would
be a pity) or they will come back later saying "labels are great! why
does the standard library lacks labels?". I would prefer the standard
library to have labels at the right places. IMHO there are still
possible improvements with respect to this issue. For instance in Map
you can find

val add : key:key -> data:'a -> 'a t -> 'a t
val find : key -> 'a t -> 'a
val remove : key -> 'a t -> 'a t

which is not really uniform (moreover, I never remember whether 
it is find : key -> 'a t -> 'a or find : 'a t -> key -> 'a so I would
like to have find : key:key -> 'a t -> 'a)

Judicaël.
-- 
Judicael.Courant@lri.fr, http://www.lri.fr/~jcourant/
(+33) (0)1 69 15 64 85
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