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Postings from February 2003
On Thursday 13 February 2003 17:54, Tim Bunce wrote:
> Sure. [I think I sounded more harsh than I meant.]
>
> Modules that only live inside the perl distribution can be
> changed in pretty much any compatible way with new releases.
>
> But for modules that have a dual life on CPAN I'd be less
> comfortable with adding an extra dependency.
It only lives on CPAN because it has no where else to live at the moment. The
interface comes from me looking at lots of core modules, seeing how they use
Exporter and making it easy. I don't see it changing very much if at all as
there's not that much else one can do with Exporter that isn't covered. I've
also written scripts to compare the EXPORT_blah variables before and after,
so that any changes can be checked for disruption.
That said, it doesn't require anything special features of Perl so it should
be available on CPAN too.
I wasn't suggesting that anything was broken but about 170 core modules use
Exporter and the same programming maneuvers are shared throughout them.
This module just encapsulates these maneuvers in one place and also prevents
other people in the future having reinvent them. I'm not hugely enthusiastic
about going through 170 modules but I'm at a bit of a loose end at the
moment, so I'm willing to do it.
There is of course a speed overhead but, to my surprise, benchmarks show that
the relatively common
eval <<'EOM',
our(@EXPORT, @EXPORT_OK, %EXPORT_TAGS, @ISA);
@ISA = ('Exporter');
@EXPORT = qw(getservbyname getservbyport getservent getserv);
@EXPORT_OK = qw( $s_name @s_aliases $s_port $s_proto );
%EXPORT_TAGS = (FIELDS => [ @EXPORT_OK, @EXPORT ] );
use vars grep /^\$/, @EXPORT_OK;
EOM
and
eval <<'EOM',
use Exporter::Easy(
EXPORT => [qw(getservbyname getservbyport getservent getserv)],
OK => [qw( $s_name @s_aliases $s_port $s_proto )],
ALL => 'FIELDS',
take the same time .0007s. In other common cases Easy is about 50% slower but
avoids having to list symbols twice.
Both of these are dominated by the cost of requiring an extra file but on my
desktop,
do "Exporter.pm"
takes .0035s and
do "Exporter.pm";do "Exporter/Easy.pm"
takes .0106s.
For this you get compile time error checking, much more flexibilty when
building %EXPORT_TAGS and elimination of repetitive lists of symbols and
tricks.
F
--
Do you need someone with lots of Unix sysadmin and/or lots of OO software
development experience? Go on, giz a job.
My CV - http://www.fergaldaly.com/cv.html
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