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Postings from October 2016
On Tue, Sep 27, 2016 at 3:47 PM, Aristotle Pagaltzis <pagaltzis@gmx.de> wrote:
> * Ævar Arnfjörð Bjarmason <avarab@gmail.com> [2016-09-27 14:36]:
>> I just couldn't find the part in the core that would allow me to
>> distinguish between:
>>
>> # should not die
>> $ perl -wE 'package Foo {}; Foo->import'
>> # should die
>> $ perl -wE 'package Foo {}; Foo->import(qw(bar))'
>
> Seems easy?
>
> $ perl -MO=Concise -e'Foo->import'
> 7 <@> leave[1 ref] vKP/REFC ->(end)
> 1 <0> enter ->2
> 2 <;> nextstate(main 1 -e:1) v:{ ->3
> 6 <1> entersub[t1] vKS/TARG ->7
> 3 <0> pushmark s ->4
> 4 <$> const(PV "Foo") sM/BARE ->5
> 5 <$> method_named(PV "import") ->6
> -e syntax OK
>
> $ perl -MO=Concise -e'Foo->import(1)'
> 8 <@> leave[1 ref] vKP/REFC ->(end)
> 1 <0> enter ->2
> 2 <;> nextstate(main 1 -e:1) v:{ ->3
> 7 <1> entersub[t1] vKS/TARG ->8
> 3 <0> pushmark s ->4
> 4 <$> const(PV "Foo") sM/BARE ->5
> 5 <$> const(IV 1) sM ->6
> 6 <$> method_named(PV "import") ->7
> -e syntax OK
>
> If I read this right, the arguments are already on the stack by the time
> that Perl_gv_fetchmethod_pvn_flags gets called.
I tried grepping around but couldn't find this, can you or anyone else
here point out what API I'm supposed to be using in
Perl_gv_fetchmethod_pvn_flags to get at these arguments?
>> I.e. perl will just ignore missing import/unimport routines, that's
>> the bit in the core I patche (to not ignore them for UNIVERSAL), but
>> maybe there's a better way.
>
> If what I said is right, then you’d need to add a check for whether the
> method is being called with arguments. Then just delete the import sub
> from UNIVERSAL (which leaves the file without any code). That should add
> up to the right thing happening, no?
>
>> I guess I'd need to patch pp_entersub for that to work, unless anyone
>> has better ideas. I.e. check if $pkg eq "UNIVERSAL" and $sub ~~
>> [qw(import unimport)] on every call, which would be quite nasty.
>
> Yeah, too nasty to do it that.
>
> Regards,
> --
> Aristotle Pagaltzis // <http://plasmasturm.org/>
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