Re: [Xen-devel] [PATCH v5 2/3] arm: Allow the user to specify the GIC version

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Wed, 2015-07-08 at 15:08 +0100, Rob Hoes wrote:
> 
> > On 8 Jul 2015, at 12:37, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote:
> > ...
> > 
> > I have a patch to genwrap.py which results in the following diff to the
> > generate ml files for the anonymous sub-struct added by the IDL change
> > above.
> > 
> > Dave/Euan/Rob, is that idiomatic ocaml or is it possible to have
> > anonymous structs in ocaml like it is in C?
> 
> I think that you have done the right thing. Iâm not sure if you can
> define a nested record type without giving the inner one a name. But
> frankly, I donât think there is much point to that either.

Thanks.

>  In fact, Iâd even drop the "__anonâ and use the struct name as the
> type name directly.

I did have that to start with, see below for how the keyed union stuff
worked which lead me to suffix it.

> Or for consistency, use "type_<name>â, which is similar to what
> happens in the keyed union case (âtype_hvm", âtype_pvâ).

Actually in this case the "type" is the name of the KeyedUnion and the
hvm|pv are the potential values of the enum which is the key.

>  Incidentally, those structs are also defined as "Struct(None, [...â,
> but are probably handled specially because the struct appears inside
> the union.

Correct, they needed different special handling of the struct in order
to construct the keyedunion as an ocaml discriminated type thing, which
ends up with (for a keyedunion key field "type" of the domain type
enum):
        type type_hvm = { ... }
        type type_pv = { ... }
        type type__union = Hvm of type_hvm | Pv of type_pv | Invalid

then the field is "xl_type : type__union";

(the xl_ prefix is because type, the name of the C field, is an ocaml
keyword...)

I added the __anon suffix for consistency with the __union suffix here.

Ian.



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