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Postings from February 2003
Fergal Daly:
# On Tuesday 11 February 2003 20:07, John Peacock wrote:
# > I think Brent is just more concerned about what happens
# when a module
# > uses the new interface, but the user doesn't have that version of
# > Exporter available. Having an ugly effect on earlier Perl's is not
# > good, no matter how nice the improvements are.
#
# I think Brent's point was that if people start taking
# advantage of this nice
# interface for their modules, then their modules will not work
# on earlier
# Perl's that don't have it. My point is that people can
# totally ignore this
# interface, it has zero effect on any module that doesn't
# about know it. It
# might be enough to just tell module authors not to use it if
# they are going
# to distribute their module to users of older Perls.
No, John interpreted correctly. I'm worried about people using this
feature without realizing that it's not backwards-compatible[1].
# It's no worse than writing modules that use 5.6 style
# attributes when there
# were lots of people who didn't have 5.6.
#
# > > Alternatively, I could just move the whole thing into
# EasyExporter
# > > or Exporter::Easy as it is totally independent of the guts of
# > > Exporter. That makes it easy for people to install it on an old
# > > version too.
# >
# > I suggest you follow this route and create Exporter::Easy as you
# > mentioned; then, if the pumpking deems this a worthy
# addition to the
# > core, you can make sure that 'use Exporter::Easy' is effectively a
# > no-op for Perl > 5.9.0.
#
# Yup, done.
#
# I've also added Exporter::Easiest which lets you do this
#
# use Exporter::Easiest q(
# OK => munge frobnicate
# EXPORT => :tag1
# TAGS =>
# :tag1 => a b c
# :tag2 => :tag1 d e f
# FAIL => f g h
# );
#
# No need for horrible []s and qw()s and ,s all over the place.
# I've uploaded it
# to CPAN but I'm not sure how long that'll take so you can get
# it from this
# directory too
My idea of an 'easiest' exporter interface is something like:
use Exporter::Easiest
':default' => qw(foo),
':all' => [qw(bar baz quux)], #Not needed but OK
':tag1' => qw(bar baz),
':tag2' => qw(:tag1 foo);
In other words, the logic is something like:
sub process_args {
my(%tags, $tag);
while(@_) {
local $_=pop;
if(exists $tags{$_}) {
$_=$tags{$_};
}
if(ref $_) {
push @{$tags{$tag}}, @$_;
}
elsif(/^:/) {
$tag=$_;
}
else {
push @{$tags{$tag}}, $_;
}
}
return %tags;
}
(Where the calling routine would use %tags to do something useful.)
--Brent Dax <brentdax@cpan.org>
@roles=map {"Parrot $_"} qw(embedding regexen Configure)
>How do you "test" this 'God' to "prove" it is who it says it is?
"If you're God, you know exactly what it would take to convince me. Do
that."
--Marc Fleury on alt.atheism
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