From: Ville-Pertti Keinonen <will@exomi.com>
To: Francois Rouaix <francois@rouaix.org>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] mystified by typing of optional arguments
Date: Thu, 3 Apr 2003 18:05:37 +0300 [thread overview]
Message-ID: <B9FC9C23-65E5-11D7-BBC9-000393863F70@exomi.com> (raw)
In-Reply-To: <A5D19256-65E3-11D7-8811-000A95773ED2@rouaix.org>
> The following example mystifies me
>
> let f ?opt x =
> match opt with
> | None -> x
> | Some dx -> x + dx
>
> let g x = x + 1
>
>
> let h1 = function
> | 0 -> [g]
> | _ -> [f; g]
>
>
> let h2 = function
> | _ -> [f; g]
>
>
> h1 is typable but not h2.
> Why is that ?
The type of the list is inferred from the first element of the first
instance.
Similarly:
let x = [ g; f ] (* works *)
let x = [ f; g ] (* doesn't work *)
let x = [ (f : int -> int); g ] (* works *)
-------------------
To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr
Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/
Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
next prev parent reply other threads:[~2003-04-03 15:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-03 14:50 Francois Rouaix
2003-04-03 15:04 ` Francois Thomasset
2003-04-03 15:05 ` Ville-Pertti Keinonen [this message]
2003-04-03 15:08 ` Eric C. Cooper
2003-04-03 15:13 ` Jacques Carette
2003-04-04 0:36 ` Jacques Garrigue
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=B9FC9C23-65E5-11D7-BBC9-000393863F70@exomi.com \
--to=will@exomi.com \
--cc=caml-list@inria.fr \
--cc=francois@rouaix.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).