Hi Yaron,
On Tue, 2010-11-09 at 22:45 -0500, Yaron Minsky wrote:
This is probably a minority opinion, but I have written and read quite
a lot of OCaml code over the years, and I've seen surprisingly few
effective uses of the composition operator. Somehow, I usually find
that code that avoids it is simpler and easier to read.
I know what you mean - it can make some code more obtuse than just doing
the same thing with a lambda. But I can't help but get the feeling it
has a place here: (note: example is semi-contrived and there are plenty
of better ways to do this, but just as an example)
module CGI =
struct
(* ... *)
let escape =
let replace = Str.global_replace - Str.regexp_string in
(replace \ quot;) - (replace ' #039;) - (replace
amp;)
Particularly the second line of `escape', where the escaping mechanism
is indeed a composition of the three replaces as specified.
Comparing that to this:
let escape s =
let replace = (* ... *) in
replace \ quot; (replace ' #039; (replace amp; s))
.. I prefer the former, as the latter forces me to specify an argument,
and nest the calls to replace. I'm not sure if there are any performance
benefits/losses as a result of computing the function `escape' in the
first example, either, but it's a consideration.
I'm not averse to infix operators. At Jane Street we've found the
following sequencing operator to be highly useful:
let ( |! ) x f = f x
and it is indeed part of the default include in Jane Street's Core
library.
That looks neat, and I imagine it to be useful, but I can't think of a
concrete use-case off the cuff. Could you give an example?
y
Cheers,
Arlen
On Tue, Nov 9, 2010 at 10:19 PM, Arlen Christian Mart Cuss
ar...@noblesamurai.com wrote:
Hi all,
I know this was asked at least 12 years ago[1], but is there
any
consensus or reason for there not being a compose function
in standard
OCaml, nor an infix operator?
At the moment I tend to let compose or let (-) f g x = f
(g x),
but I wish I didn't have to!
Thanks,
Arlen
[1]
http://webcache.googleusercontent.com/search?q=cache:TcqI7o37il8J:pauillac.inria.fr/caml/caml-list/0720.html+ocaml+function+composecd=2hl=enct=clnkclient=ubuntu
___
Caml-list mailing list. Subscription management:
http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list
Archives: http://caml.inria.fr
Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
Bug reports: http://caml.inria.fr/bin/caml-bugs
___
Caml-list mailing list. Subscription management:
http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list
Archives: http://caml.inria.fr
Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
Bug reports: http://caml.inria.fr/bin/caml-bugs
___
Caml-list mailing list. Subscription management:
http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list
Archives: http://caml.inria.fr
Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
Bug reports: http://caml.inria.fr/bin/caml-bugs
