Re: [Qemu-devel] [PATCH v2 17/29] qapi: Record 'include' directives in intermediate representation

[Eric Blake <eblake@redhat.com>]

On 02/11/2018 03:35 AM, Markus Armbruster wrote:
> The include directive permits modular QAPI schemata, but the generated
> code is monolithic all the same.  To permit generating modular code,
> the front end needs to pass more information on inclusions to the back
> ends.  The commit before last added the necessary information to the
> parse tree.  This commit adds it to the intermediate representation
> and its QAPISchemaVisitor.  A later commit will use this to to
> generate modular code.
> 
> New entity QAPISchemaInclude represents inclusions.  Call new visitor
> method visit_include() for it, so visitors can see the sub-modules a
> module includes.
> 
> Note that unlike other entities, QAPISchemaInclude has no name, and is
> therefore not added to entity_dict.
> 
> New QAPISchemaEntity attribute @module names the entity's source file.
> Call new visitor method visit_module() when it changes during a visit,
> so visitors can keep track of the module being visited.
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
> @@ -1479,16 +1497,19 @@ class QAPISchema(object):
>           self._entity_dict = {}
>           self._predefining = True
>           self._def_predefineds()
> -        self._predefining = False
>           self._def_exprs(exprs)
>           self.check()

Why does self._predfining not need to be toggled anymore?  Do we even 
need this variable any more...

> 
>      def _def_entity(self, ent):
>          # Only the predefined types are allowed to not have info
>          assert ent.info or self._predefining
> -        assert ent.name not in self._entity_dict

...and/or is this assert now worthless?


> +++ b/tests/qapi-schema/comments.out
> @@ -1,4 +1,5 @@
>   object q_empty
>   enum QType ['none', 'qnull', 'qnum', 'qstring', 'qdict', 'qlist', 'qbool']
>       prefix QTYPE
> +module comments.json
>   enum Status ['good', 'bad', 'ugly']

Based on the generated output, it looks like you can tell whether you 
are in the predefining stage by not having any module at all; the first 
visit_module call is what flips the switch that everything else is 
defined by a module and must therefore have associated info.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org