Re: [Cocci] Changing format string usage with SmPL?

[Markus Elfring <Markus.Elfring@web.de>]

> OK, if you may have more than one argument to your print,
> then you can find the offset using an expression list metavariable:
>
> @r@
> expression list[n] between;
> @@
>
> print(s,between,h2->name,...)
>
> Then you can use r.n in your python rule to figure out where is the %s to change.

This data processing approach sounds promising.


> Unfortunately, this will not work well if there are multiple name references in the argument list.

I hope that the Coccinelle software can help more with the analysis
for format strings.


> Because you will be trying to change the format string in multiple ways,
> eg once where between has length 2 and once where between has length 4.

This can probably happen.


> Substantial hacks would be required to deal with this.

How can corresponding collateral evolution be better supported?


> It would be nice if you could do
>
> @r@
> expression list[bn] between;
> expression list[an] after;
> position p;
> @@
> print@p(s,between,name,after)
>
> @@
> format list[r.bn] f1;
> format list[r.an] f2;
> position r.p;
> @@
> print@p(
> -    "%@f1@%s%@f2@"
> +   "%@f1@%m%@f2@"
> , l)
>
> I don't know if that would work, though.

I find this information interesting.
How will the clarification be continued for affected open issues?

Regards,
Markus
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