Re: [Cocci] Replacing a struct member with a function call

[Thomas Adam <thomas@xteddy.org>]

Hello,

I can see I was as clear as mud with my explanation -- apologies for
that, so let me try again.

In my original example:

struct monitor {
    struct {
        int width;
        int height
    } virtual;
};

... the members width and height aren't required any more, as they're
actually computable generically, and don't belong in that struct.
Instead, I have separate functions which can provide those values.

So where I have in code, statements such as:

struct monitor *m = this_monitor();
int foo = m->virutal.width;

I want to be able to substitute "m->virtual.width" with a function
call "get_width()" -- which does not involve "struct monitor" at all.
Indeed, the semantic patch I'm trying to apply now looks like this:

@@
struct monitor *m;
@@

- m->virtual.width;
+ get_width();

... and although spatch doesn't tell me of any errors, when I run it
over my codebase, no modifications are made.  So clearly I'm still
doing something wrong.  At the point, I have some questions:

1.  Given the inner struct "virtual" inside of "struct monitor", is it
correct that spatch would understand:

m->virtual.width;

... or do I need to declare "virtual" as some expression or
identifier?  I did try:

@@
struct monitor *m;
expression virtual;
@@

- m->virtual.width;
+ get_width();

... but this results in an error.

2.  Do I need to declare "virtual" as a struct in its own right
somehow?  If so, it's not immediately obvious if this should be the
case or how to do it.

I hope I'm making some sense here -- apologies if not, and if I need
to expand upon anything further, do please let me know.

Essentially, it seems to me as though the inner struct "virtual" isn't
being declared as a valid type which spatch is understanding, and this
is why things aren't working how I'd like.

Again, thanks ever so much for you time -- everyone's been very
helpful to me in the past, and I've found coccinelle to be invaluable
to making sweeping code changes, as well as bug-fixes on my codebase,
so thanks to everyone involved in this project.  It's invaluable!

Kindly,
Thomas

On Sun, 14 Mar 2021 at 09:16, Julia Lawall <julia.lawall@inria.fr> wrote:
>
>
>
> On Sun, 14 Mar 2021, Wolfram Sang wrote:
>
> >
> > > @@
> > > type M;
> >
> > This?
> >
> > struct monitor* m;
> >
> > > @@
> > > - m->virtual.width;
> > > + get_monitor_width();
>
> I guess that m should be somewhere in teh call to get_monitor_width too?
>
> julia
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