in reply to Re: Can I check if a loop's scope is entered for the first time?
in thread Can I check if a loop's scope is entered for the first time?
From what I see in the sources of Var::Pairs are you binding a cycling iterator to the call place with the help of Devel::Callsite .
This is just a more secure way of using line and file from caller .
But this will only work well if you always finish the loop without exiting in the middle, since you are only initializing once by the first entry and letting the iteration starting new after a full loop.
What I'm looking for is to re-init the iterator when it is re-entered again. Hence to safely use last and return or other loop exits.
Consider this example showing that your iterators are not reset after breaking the loop.
use warnings; use strict; use feature 'say'; use Var::Pairs; my %hash; @hash{"a".."d"} =1..4; sub till { my $goal = shift; while (my $next = each_pair %hash) { say $next->key, ' had the value ', $next->value; last if $next->key eq $goal; } say "-"x10 . "exit"; } till("a"); till("a"); till("a"); till("a");
/usr/bin/perl -w /home/lanx/pm/t_var_pairs.pl a had the value 1 ----------exit d had the value 4 b had the value 2 c had the value 3 ----------exit a had the value 1 ----------exit d had the value 4 b had the value 2 c had the value 3 ----------exit Compilation finished at Sun May 6 21:54:21
update
NB: each has of course the same (and more) limitations.
Cheers Rolf
(addicted to the Perl Programming Language and ☆☆☆☆ :)
Wikisyntax for the Monastery
*) There are different kinds of iterators, please correct me if I'm missing a way to apply this to my kind of iterators ...
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Re^3: Can I check if a loop's scope is entered for the first time? (Devel::Callsite)
by TheDamian (Vicar) on May 07, 2018 at 04:11 UTC | |
by TheDamian (Vicar) on May 07, 2018 at 05:03 UTC | |
by TheDamian (Vicar) on May 07, 2018 at 06:09 UTC | |
by TheDamian (Vicar) on May 07, 2018 at 13:58 UTC | |
by LanX (Saint) on May 07, 2018 at 16:41 UTC | |
by Anonymous Monk on May 07, 2018 at 18:50 UTC | |
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