[Cocci] Adding a newline after a variable definition

[Cocci] Adding a newline after a variable definition

[Fuad Tabba]

Hi,

I have a semantic patch that inserts a new variable definition into a
function. I would like it if that variable definition is the only one
in the function, then it should add a new line to separate the
definition from following statements (Linux code formatting style).

I thought that doing this in two steps might be easier, i.e., add the
definition, then check and add a newline if a statement follows:

@@
identifier x;
identifier func;
statement S;
@@
func(...)
 {
struct kvm_cpu_context *x = ...;
+ newline;
S
...
 }

The above works as expected, and it adds "newline;" after the
definition of x. The thing is, is it possible to add an actual new
line, as opposed to a non-whitespace string? I tried just using a +
but that didn't work.

Thanks!
/fuad
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Re: [Cocci] Adding a newline after a variable definition

[Julia Lawall]

On Wed, 23 Jun 2021, Fuad Tabba wrote:

> Hi,
>
> I have a semantic patch that inserts a new variable definition into a
> function. I would like it if that variable definition is the only one
> in the function, then it should add a new line to separate the
> definition from following statements (Linux code formatting style).
>
> I thought that doing this in two steps might be easier, i.e., add the
> definition, then check and add a newline if a statement follows:
>
> @@
> identifier x;
> identifier func;
> statement S;
> @@
> func(...)
>  {
> struct kvm_cpu_context *x = ...;
> + newline;
> S
> ...
>  }
>
> The above works as expected, and it adds "newline;" after the
> definition of x. The thing is, is it possible to add an actual new
> line, as opposed to a non-whitespace string? I tried just using a +
> but that didn't work.

I think that the problem is not that the change is not being made, but
that spatch doesn't think it's worth showing you the change, since the
only change is in the whitespace.  Try adding the argument --force-diff

Note that you can cause this argument to always be used with your semantic
patch by putting

#spatch --force-diff

at the top of the file.

julia
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Re: [Cocci] Adding a newline after a variable definition

[Fuad Tabba]

That works, thank you!

Cheers,
/fuad

On Wed, Jun 23, 2021 at 9:54 AM Julia Lawall <julia.lawall@inria.fr> wrote:
>
>
>
> On Wed, 23 Jun 2021, Fuad Tabba wrote:
>
> > Hi,
> >
> > I have a semantic patch that inserts a new variable definition into a
> > function. I would like it if that variable definition is the only one
> > in the function, then it should add a new line to separate the
> > definition from following statements (Linux code formatting style).
> >
> > I thought that doing this in two steps might be easier, i.e., add the
> > definition, then check and add a newline if a statement follows:
> >
> > @@
> > identifier x;
> > identifier func;
> > statement S;
> > @@
> > func(...)
> >  {
> > struct kvm_cpu_context *x = ...;
> > + newline;
> > S
> > ...
> >  }
> >
> > The above works as expected, and it adds "newline;" after the
> > definition of x. The thing is, is it possible to add an actual new
> > line, as opposed to a non-whitespace string? I tried just using a +
> > but that didn't work.
>
> I think that the problem is not that the change is not being made, but
> that spatch doesn't think it's worth showing you the change, since the
> only change is in the whitespace.  Try adding the argument --force-diff
>
> Note that you can cause this argument to always be used with your semantic
> patch by putting
>
> #spatch --force-diff
>
> at the top of the file.
>
> julia
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