Re^2: Yet more Try::Tiny problelms

And, bingo!

#! /usr/bin/perl

use feature qw (switch);
use Try::Tiny;

my $uv;
given (17) {
    when (3) { print "three\n"; };
    when (17) {
    try {
        print "In try block\n";
        die( "Substitute undefined variable $uv\n");
        print "Still in try block\n";
    } catch {
        print "We caught $_\n";
    };
    }
}
[download]

Output is:

$ ./t4.pl 
In try block
We caught 17

It was indeed an interaction between Try::Tiny and the switch feature. Might not happen in later versions of Perl, according to what I've read, but we're running 5.10, where it does.

Comment on Re^2: Yet more Try::Tiny problelms Download Code

Replies are listed 'Best First'.
Re^3: Yet more Try::Tiny problelms by tobyink (Canon) on May 19, 2013 at 17:55 UTC
It works more sanely in Perl 5.18... `In try block We caught Substitute undefined variable` [download] For Perl 5.10-5.16, the easiest fix is: `catch { our $_; # stop lexical $_ from masking global $_ print "We caught $_\n"; }` [download] `package Cow { use Moo; has name => (is => 'lazy', default => sub { 'Mooington' }) } say Cow->new->name`	[reply] [d/l] [select]
Re^4: Yet more Try::Tiny problelms by dd-b (Monk) on May 19, 2013 at 23:08 UTC
Or use "for" instead of "given" to kick things off.	[reply]
Re^3: Yet more Try::Tiny problelms by Anonymous Monk on May 19, 2013 at 17:43 UTC
:) happens in v5.16.1 also, but if you search Try::Tiny for $_ this caveat is described *but real* solution is not** I found this thread I participated in Lexical $_ in given/when vs. BLOCK arguments which had the real solution, because I ran into similar nonsense before :) #!/usr/bin/perl -- use feature qw (switch); use Try::Tiny; my $uv; given (17) { when (3) { print "three\n"; }; when (17) { #~ local $_; # grr Can't localize lexical variable $_ #~ my $_; ## doesn't help, Try::Tiny code is using global $_ #~ local *_; ## doesn't help , here $_ refers to lexical $_ our $_; # THIS HELPS try { print "In try block\n"; die( "Substitute undefined variable $uv\n"); print "Still in try block\n"; } catch { print "We caught global \$@ = $@\n"; print "We caught lexical \$_ = $_\n"; print "We caught global \$::_ = $::_\n"; print "We caught global \$_[0] = $_[0]\n"; }; } } __END__ In try block We caught global $@ = We caught lexical $_ = Substitute undefined variable We caught global $::_ = Substitute undefined variable We caught global $_[0] = Substitute undefined variable [download] So summary, local $_ should NOT die but work just like our $_ inside given/when Try::Tiny documentation should lead with $::_ I still don't think in terms of given/when -- well I do, but I spell it if/else/unless :D	[reply] [d/l]
Re^4: Yet more Try::Tiny problelms by Anonymous Monk on May 19, 2013 at 19:52 UTC
Perl::Critic::Policy::ValuesAndExpressions:: GivenWhenTryCatchLexicalDollarUnderDefaultVarBindingConfusion `perlcritic -3 warnmeaboutthis.pl lexical $_ from given/when in catch(from Try::Tiny) but you probably w +anted global $_, use $::_ instead at line 11, column 5. do you want + my/lexical $_ or global $_?. (Severity: 3)` [download]	[reply] [d/l]


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