in reply to Recover a variable from a loop

Declare them. If you don't know what the implications are of an error message you can always use diagnostics:

$ perl -Mstrict -Mdiagnostics -e '$x=1;'
Global symbol "$x" requires explicit package name at -e line 1.
Execution of -e aborted due to compilation errors (#1)
    (F) You've said "use strict" or "use strict vars", which indicates
+ 
    that all variables must either be lexically scoped (using "my" or 
+"state"), 
    declared beforehand using "our", or explicitly qualified to say 
    which package the global variable is in (using "::").
    
Uncaught exception from user code:
        Global symbol "$x" requires explicit package name at -e line 1
+.
        Execution of -e aborted due to compilation errors.

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Re^2: Recover a variable from a loop
by Chaoui05 (Scribe) on May 26, 2016 at 09:01 UTC
    Thanks for the tool. I thought about that but i already declare my variable in my loop. I just want to recover them in this code part 
     unless ($white{browser_name => $browser[0]}->compare($blue{browser_na
+me => $browser[1]})) {
    $diff_file = $white->difference($blue);
    print '#The images differ; see ' . $diff_file . ' for details'. "\
+n";
  

  my $open_cmd;
  if ($^O eq 'darwin') {
      $open_cmd = 'open'
  }
  elsif ($^O eq 'MSWin32') {
      $open_cmd = '';
  }
  else {
      $open_cmd = 'display';
  }
  `$open_cmd $diff_file`;
  }

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    Lost in translation
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      but i already declare my variable in my loop

      No, you don't. You have not declared $diff_file in any part of the code which you have shown.

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        For this variable yes. I've just done it. But for $white, it's done .
        Lost in translation
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      unless ($white{browser_name => $browser[0]}->compare($blue{browser_name => $browser[1]})) {
         $diff_file = $white->difference($blue);
         print '#The images differ; see ' . $diff_file . ' for details'. "\n";
         ...
         }

      I don't understand what you're trying to do with an expression like $white{browser_name => $browser[0]}, but I doubt it's the right way to go.

      You're trying to use the old fashioned (pre-Perl 5) multidimensional array hack | emulation on the hash  %white which you have never declared. (Update: You're not accessing the  $white object reference.) 

      c:\@Work\Perl\monks>perl -wMstrict -le
"use Data::Dump qw(dd);
 ;;
 my %white;
 ;;
 my @bar = qw(bozzle);
 ;;
 $white{ foo => $bar[0] } = 'wibble';
 dd \%white;
"
{ "foo\34bozzle" => "wibble" }

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      The  "foo\34bozzle" key in the dd dump is part of this old hack. See  $; in perlvar for some info on this. I'd like to give you a more complete reference, but I can't seem to find one ATM. (Anyone...?) (Update: Ok, there's this brief discussion on-line in perldata: Multi-dimensional array emulation.)

      Give a man a fish:  <%-{-{-{-<

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