Re: [PATCH v5 3/9] qapi: make gen_if/gen_endif take a simple string

["Marc-André Lureau" <marcandre.lureau@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 2435 bytes --]

Hi

On Mon, Jun 14, 2021 at 4:48 PM Markus Armbruster <armbru@redhat.com> wrote:

> marcandre.lureau@redhat.com writes:
>
> > From: Marc-André Lureau <marcandre.lureau@redhat.com>
> >
> > Instead of building prepocessor conditions from a list of string, use
> > the result generated from QAPISchemaIfCond.cgen().
>
> I understand why you're doing this, but only because I know where you're
> headed.  By itself, it is not an improvement: you move C generation out
> of common.py into schema.py.  You need to explain why that's useful.
>
>
What about?

In the following commits, QAPISchemaIfCond is going to hold an internal
tree structure. Moving cgen() there allows to abstract away the condition
representation.



> > diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
> > index bc357ebbfa..aa4715c519 100644
> > --- a/scripts/qapi/schema.py
> > +++ b/scripts/qapi/schema.py
> > @@ -29,6 +29,9 @@ class QAPISchemaIfCond:
> >      def __init__(self, ifcond=None):
> >          self.ifcond = ifcond or []
> >
> > +    def cgen(self):
> > +        return ' && '.join(self.ifcond)
>
> Fragile.  Better:
>
>            return '(' + ') && ('.join(self.ifcond) + ')'
>
>
This is an intermediary step, but ok.

If we want to keep C generation details out of schema.py, we need a
> helper mapping self.ifcond: Sequence[str] to C code, similar to how
> QAPISchemaEntity.c_name() works with helper c_name().
>

Leaving a FIXME.


> > +
> >      # Returns true if the condition is not void
> >      def __bool__(self):
> >          return bool(self.ifcond)
> > diff --git a/scripts/qapi/types.py b/scripts/qapi/types.py
> > index 3673cf0f49..db9ff95bd1 100644
> > --- a/scripts/qapi/types.py
> > +++ b/scripts/qapi/types.py
> > @@ -51,13 +51,13 @@ def gen_enum_lookup(name: str,
> >  ''',
> >                  c_name=c_name(name))
> >      for memb in members:
> > -        ret += gen_if(memb.ifcond.ifcond)
> > +        ret += gen_if(memb.ifcond.cgen())
> >          index = c_enum_const(name, memb.name, prefix)
> >          ret += mcgen('''
> >          [%(index)s] = "%(name)s",
> >  ''',
> >                       index=index, name=memb.name)
> > -        ret += gen_endif(memb.ifcond.ifcond)
> > +        ret += gen_endif(memb.ifcond.cgen())
> >
> >      ret += mcgen('''
> >      },
> [More of the same snipped...]
>
>
>

-- 
Marc-André Lureau

[-- Attachment #2: Type: text/html, Size: 4054 bytes --]