Comment author: @damiendoligez

I don't understand the need to annoy your users by forcing them to type = instead of the large easy-to-find space bar...

The best way to implement this without polluting arg.mli too much is probably to add an optional argument to parse and parse_argv to tell them to accept = as a separator between flag and argument.

Comment author: Richard Jones

I think Arg should work like GNU getopt_long, ie. accept both --arg foo and --arg=foo.

Someone has noted that our virt-* tools written in OCaml don't behave in the expected way (https://bugzilla.redhat.com/show_bug.cgi?id=1028650).

I will try to come up with a suitable patch to the Arg module to allow it to accept both.

Comment author: Richard Jones

Sorry, I uploaded the wrong file first time. Please delete the first attachment (I can't work out how to delete attachments in Mantis).

I am testing this patch:
0001-stdlib-arg-Allow-flags-such-as-flag-arg-as-well-as-f.patch

Comment author: Richard Jones

FWIW I have been trying out my patch since 2013-11-09 with no
apparent problems. I have pushed this patch into Fedora to get
wider testing.

Comment author: alavrik

It looks like there may be a problem with this patch (assuming this is the same one that was pushed with the current Fedora).

The actual problem seems to be that Arg.current has incorrect value (at least in some cases). The value is off by +1 from the value in the stock OCaml version.

Please see this discussion for the details and steps to reproduce the problem: https://groups.google.com/d/msg/piqi/SZ97hEf8j7I/taK1eUx-AigJ

And here's the actual code that exposes the difference in behavior: https://github.com/alavrik/piqi/blob/master/piqilib/piqi_getopt.ml#L349

Comment author: Richard Jones

Do you have a tiny reproducer of the bug?

Comment author: Richard Jones

OK here's my reproducer:

(* Run: argtest -- 1 2 3 *)
let rest_fun arg =
Printf.printf "current = %d, arg = %s\n" !Arg.current arg
let argspec = [ "--", Arg.Rest rest_fun, "sep" ]
let anon_fun arg =
Printf.printf "current = %d, anon = %s\n" !Arg.current arg
let () = Arg.parse argspec anon_fun "usage"

Without the patch, prints:

$ ./argtest -- 1 2 3
current = 1, arg = 1
current = 2, arg = 2
current = 3, arg = 3

With the patch, prints:

$ ./argtest -- 1 2 3
current = 2, arg = 1
current = 3, arg = 2
current = 4, arg = 3

So this is a real bug, I'll see what is causing it and update the
patch and the Fedora package.

Comment author: Richard Jones

Please can someone delete the attachment.

The following two patches should fix the bug properly without changing
the order in which Arg.current is incremented:

http://oirase.annexia.org/tmp/0001-arg-Add-no_arg-and-get_arg-helper-functions.patch
http://oirase.annexia.org/tmp/0002-arg-Allow-flags-such-as-flag-arg-as-well-as-flag-arg.patch

This only affects Fedora 21, and I will push a fix for it shortly.

Comment author: @gasche

Note: The two patches are available for review as a github request:
#63

Comment author: Richard Jones

The latest versions of my two patches are:

https://git.fedorahosted.org/cgit/fedora-ocaml.git/commit/?h=fedora-24-4.02&id=e48a32ed47b6b5a77653ca3b40afb7c26aca7123
https://git.fedorahosted.org/cgit/fedora-ocaml.git/commit/?h=fedora-24-4.02&id=b5e341afca2bdb390255cb74b3e3f5d1e3971590

(See also this branch: https://git.fedorahosted.org/cgit/fedora-ocaml.git/log/?h=fedora-24-4.02 )

Comment author: @damiendoligez

Fixed bug, added changelog entry and test, merged into trunk (commit 2512b48).