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Re: marking can() coderef as a method

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From:
Nick Ing-Simmons
Date:
August 24, 2001 06:29
Subject:
Re: marking can() coderef as a method
Message ID:
20010824132903.900.7@bactrian.ni-s.u-net.com
Geoffrey Young <gyoung@laserlink.net> writes:
>hi all...
>
>  I thought it might be genuinely useful to mark a coderef returned by
>UNIVERSAL::can() as being a method so that XS routines can know whether to
>use perl_call_method or perl_call_sv on it.  

I don't think so. You can always use perl_call_sv on a coderef.
The fact that ->can found it does NOT tell you whether you need 
to push the object arg - and there is no point in the perl_call_method
overhead.

>
>  please forgive me if I misunderstand the purpose of CvMETHOD_on - I
>scoured the archives but could only find a smattering of information and I'm
>probably a bit out of my league here anyway... 

CvMETHOD corresponds to the : method attribute you can give to subs.
Its original use was for Malcolm's original thread locking scheme.
A sub which had : locked and : method locked the _object_ one 
which just had : locked locked the CV itself.

One could make a case that ->can should _fail_ unless sub had : method 
attribute - but I won't 'cos lots of OO perl code (including mine)
does not annotate methods. 


>
>--Geoff
>
>this patch is against the current bleedperl available from rsync - a clean
>build passes all tests on my system.
>
>--- universal.c.old	Thu Aug 23 13:14:18 2001
>+++ universal.c	Thu Aug 23 13:38:27 2001
>@@ -219,8 +219,10 @@
> 
>     if (pkg) {
>         GV *gv = gv_fetchmethod_autoload(pkg, name, FALSE);
>-        if (gv && isGV(gv))
>+        if (gv && isGV(gv)) {
>+	    CvMETHOD_on(GvCV(gv));
> 	    rv = sv_2mortal(newRV((SV*)GvCV(gv)));
>+        } 
>     }
> 
>     ST(0) = rv;
-- 
Nick Ing-Simmons
http://www.ni-s.u-net.com/


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