On Thu, Dec 6, 2018 at 10:14 PM Markus Armbruster <arm...@redhat.com> wrote:
>
> Marc-André Lureau <marcandre.lur...@redhat.com> writes:
>
> > Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
> > ---
> > docs/devel/qapi-code-gen.txt | 19 +++++++++++++++++++
> > 1 file changed, 19 insertions(+)
> >
> > diff --git a/docs/devel/qapi-code-gen.txt b/docs/devel/qapi-code-gen.txt
> > index c2e11465f0..799aef7728 100644
> > --- a/docs/devel/qapi-code-gen.txt
> > +++ b/docs/devel/qapi-code-gen.txt
> > @@ -752,6 +752,25 @@ gets its generated code guarded like this:
> > #endif /* defined(HAVE_BAR) */
> > #endif /* defined(CONFIG_FOO) */
> >
> > +Where a member can be defined with a single string value for its type,
> > +it is also possible to supply a dictionary instead with both 'type'
> > +and 'if' keys.
> > +
> > +Example: a conditional 'bar' member
> > +
> > +{ 'struct': 'IfStruct', 'data':
> > + { 'foo': 'int',
> > + 'bar': { 'type': 'int', 'if': 'defined(IFCOND)'} } }
> > +
> > +An enum value can be replaced by a dictionary with a 'name' and a 'if'
> > +key.
> > +
> > +Example: a conditional 'bar' enum member.
> > +
> > +{ 'enum': 'IfEnum', 'data':
> > + [ 'foo',
> > + { 'name' : 'bar', 'if': 'defined(IFCOND)' } ] }
> > +
> > Please note that you are responsible to ensure that the C code will
> > compile with an arbitrary combination of conditions, since the
> > generators are unable to check it at this point.
>
> I'd prefer to update qapi-code-gen.txt right when we extend the schema
> language, like you did in part 1 (commit 967c885108f qapi: add 'if' to
> top-level expressions). I understand it's a bit more churn, since you
> need four steps (enum, struct, union, alternate members). I think the
> following would be the least work for you that still satisfies me:
>
> * Add the part about enum values in PATCH 13.
>
> * Add the rest in PATCH 17 (the first patch that implements a part of
> it), with a TODO implement <list of things that get done in later
> patches>. Then just update the TODO as you go.
>
> Okay?
Easy enough, done.
