[27790] in Perl-Users-Digest
Perl-Users Digest, Issue: 9154 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Fri Apr 14 00:05:49 2006
Date: Thu, 13 Apr 2006 21:05:05 -0700 (PDT)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Thu, 13 Apr 2006 Volume: 10 Number: 9154
Today's topics:
Re: tr/// broken? <nospam-abuse@ilyaz.org>
Re: XS progamming question <nospam-abuse@ilyaz.org>
Re: XS progamming question <nospam-abuse@ilyaz.org>
Re: XS progamming question <nospam-abuse@ilyaz.org>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Fri, 14 Apr 2006 02:48:06 +0000 (UTC)
From: Ilya Zakharevich <nospam-abuse@ilyaz.org>
Subject: Re: tr/// broken?
Message-Id: <e1n2h6$20h7$1@agate.berkeley.edu>
[A complimentary Cc of this posting was sent to
Dr.Ruud
<rvtol+news@isolution.nl>], who wrote in article <e1lpgl.1fk.1@news.isolution.nl>:
> In a Perl context, 'utf8' is commonly read as the proper subset of
> 'UTF-8' currently used by Perl.
utf8 is a proper SUPERSET of UTF-8. The former is not restricted to
any particular range of non-negative integers; the current
implementation goes 0..0xFFFFFFFFFFFFFFFF (i.e., maximal range of
native unsigned integers currently used in Perl), and there are "free"
bits to extend it to, e.g., 128bit - if Perl is used on architecture
with sizeof(UV) = 128bits.
UTF-8 is "legally" restricted to 0..0x1FFFFF, although technically, it
can cover up to, IIRC, 0..0x1FFFFFFF.
Hope this helps,
Ilya
------------------------------
Date: Fri, 14 Apr 2006 02:38:28 +0000 (UTC)
From: Ilya Zakharevich <nospam-abuse@ilyaz.org>
Subject: Re: XS progamming question
Message-Id: <e1n1v4$20bt$1@agate.berkeley.edu>
[A complimentary Cc of this posting was sent to
Ferry Bolhar
<bol@adv.magwien.gv.at>], who wrote in article <1144917943.448921@proxy.dienste.wien.at>:
> But what happens with this code:
Here is what the compiler translates it too:
> mysub();
This is a shortcut for
*mysub{CODE}->();
*mysub is calculated at compile time, the rest is postponed to
execution time (i.e., opcodes to calculate {CODE} and ->() are placed
into the compiled tree).
> sub mysub {
> print "This is mysub!");
> }
This is more or less equivalent to
BEGIN {
*mysub = sub {print "This is mysub!");}
}
In other words, *mysub{CODE} is populated by the subroutine reference.
> mysub();
Same as above.
Now compilation ended, and the compile tree contains code for
*mysub{CODE}->();
*mysub{CODE}->();
The code in the tree is executed. At the moment of execution the CODE
slot is defined, so you get no errors.
> BTW: is there a difference when saying
>
> package foo;
>
> $var = 1;
> sub bar {...};
>
> vs.
>
> $foo::var = 1;
> sub foo::bar {...};
Yes. The "content of sub" is compiled in a different package. The
second code is equivalent to
package foo;
$var = 1;
sub bar {
package main;
...
};
> IIUC 'package' is just a compiler directive (like 'use', 'my' and 'our'),
> never appearing in an OP tree?
There is a notion of "current package" during execution (relevant to,
at least, eval"" and caller() [what else?]). So it IS stored in the
compile tree.
Hope this helps,
Ilya
------------------------------
Date: Fri, 14 Apr 2006 02:40:50 +0000 (UTC)
From: Ilya Zakharevich <nospam-abuse@ilyaz.org>
Subject: Re: XS progamming question
Message-Id: <e1n23i$20c3$1@agate.berkeley.edu>
[A complimentary Cc of this posting was sent to
Ferry Bolhar
<bol@adv.magwien.gv.at>], who wrote in article <1144918383.68376@proxy.dienste.wien.at>:
> How subs are compiled? I guess the OP tree is generated, a CV is
> made whose START/ROOT entries will point to the first sub OP,
> and a stash entry is made (unless for anonymous sub's)?
I can find no contradiction to your description.
> > E.g., if a module contains only subroutines, "package" declarations,
> > and "1;" at the end, the only thing which is executed is this "1;".
> Unless it was included with 'use' and has an "import()" sub, right?
No. import() is executed by the "caller"/"use()r".
Hope this helps,
Ilya
------------------------------
Date: Fri, 14 Apr 2006 03:18:40 +0000 (UTC)
From: Ilya Zakharevich <nospam-abuse@ilyaz.org>
Subject: Re: XS progamming question
Message-Id: <e1n4ag$212j$1@agate.berkeley.edu>
[A complimentary Cc of this posting was sent to
<robic0>], who wrote in article <7j3u32pr72bm0tpb6t54c1aha2q0jakf2g@4ax.com>:
> > *mysub{CODE}->();
> Is this '*' used here a 'glob'?
Yes.
> Can you explain in detail just what a glob is?
You do not want to know. Just avoid them at any cost; they are just
remnants of object-less Perl4.
Hope this helps,
Ilya
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>
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End of Perl-Users Digest V10 Issue 9154
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