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Postings from August 2013
On Thu, Aug 29, 2013 at 12:48 PM, Zefram <zefram@fysh.org> wrote:
> tlhackque wrote:
> >>One might imagine a toggle object as a middle ground -- e.g.
> >> $toggle = Toggle::new( '...', sub {/^--a$/} , sub {/^--b$/}); #
>
> Can be done much more neatly by a call-checker plugin and custom ops.
> I'm thinking of it looking something like
>
> $out .= $_ if toggle /^--a$/, /^--b$/;
>
Heh. I was about to do a bit of shameless advertisement by saying that "you
can do that with Params::Lazy right now!", but turn out, you can't without
some silly workarounds, at least until I push this new version to CPAN :P
But well, this works on the dev version:
sub toggle;
use Params::Lazy toggle => q(^^);
my $toggle_state = '';
sub toggle {
my ($begin, $end) = @_;
if ( !$toggle_state ) {
$toggle_state = 1 if force $begin;
}
else {
if ( force $end ) {
$toggle_state = '';
return "1E0";
}
else {
$toggle_state++;
}
}
return $toggle_state;
}
my $out;
for (qw(no1 no2 --a first second third --b no3)) {
$out .= "<$_>" if toggle /^--a$/, /^--b$/;
}
say $out;
> Named toggles just need a slight extension to put their state somewhere
> visible. As the hiddenness of a toggle's state is a nasty aspect of
> the core feature, I'd be inclined to make these toggles use an explicit
> variable, whose lifetime can be controlled in the usual ways:
>
> my $tog;
> reset_toggle $tog;
> $out .= $_ if toggle $tog, /^--a$/, /^--b$/;
>
I believe this would "just" require extending the code above to also use
the * prototype.
>
> >>such as
> >>
> >> reset ['label']; or reset( ['label'], 2 );
>
> If a toggle reset feature is added to the core, it should not further
> overload an existing core operator, especially one that is presently
> unrelated.
>
>
+1
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