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Re: [Libguestfs] [PATCH v2 2/3] mllib: Use L"..." and S '...' for long and short options.



On Mon, Jul 18, 2016 at 05:40:11PM +0200, Pino Toscano wrote:
> On Monday, 18 July 2016 14:43:03 CEST Richard W.M. Jones wrote:
> > > > -  let validate_key key =
> > > > -    if String.length key == 0 || key == "-" || key == "--"
> > > > -       || key.[0] != '-' then
> > > > -      invalid_arg (sprintf "invalid option key: '%s'" key)
> > > > +  let validate_key = function
> > > > +    | L"" -> invalid_arg "Getopt spec: invalid empty long option"
> > > > +    | L"help" -> invalid_arg "Getopt spec: should not have L\"help\""
> > > 
> > > Theoretically both Arg and the current Getopt allow applications to
> > > provide an own handler for --help, instead of the built-in one.
> > 
> > Sure, but I don't think that's a good idea :-)
> 
> Well, I could have avoided that when proposing the final Getopt patch...
> 
> Also, there should be the same checks for M"something" of the
> L"something" ones.

How about I add this case:

   let validate_key = function
+    | M s when String.length s <> 2 || (s.[0] <> 'i' && s.[0] <> 'o') ->
+       invalid_arg "Getopt spec: invalid use of M\"...\" option - only use this for virt-v2v -iX and -oX options"
     | L"" -> invalid_arg "Getopt spec: invalid empty long option"

It effectively excludes any use of the M option except for the
special cases in virt-v2v.

> > > IMHO it'd be better to sort the specs at this point, like done before;
> > > otherwise, --help (and potentially any non-hidden built-in option added
> > > here) will be shown only at the end of the other specs.
> > 
> > At the beginning of the list, and it was deliberate.  However it's
> > just a matter of preference, and the options could be sorted later.
> 
> Well I'd prefer it sorted, since it won't create arbitrary lines of
> --help with different order, which look a bit odd.

OK, I changed the sort so it happens after the --help and other
options have been added.

> Also, making everything ordered was basically the reason for the helper
> type t, and the mutable state of its specs field.

Indeed - I couldn't work out how to rewrite the code without
mutability.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
libguestfs lets you edit virtual machines.  Supports shell scripting,
bindings from many languages.  http://libguestfs.org


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