Re: (tye)Re: our/my inconsistency.

It looks like strict and warnings won't be entirely strict on subroutines and my.

use strict;
use warnings;

  my %hash = (one   => "one",
              two   => "two",
              three => "three" );

  print "$hash{one}\n";
  test();
exit;

sub test {
  for (keys %main::hash) {
   print "$_ $main::hash{$_}\n";
  }
}
[download]

This will print one.
Substituting our for my will print something more expected.
Interesting behaviour.
Update:
Try it out with arrays and a scalar.
An array will warn of a var used once.
A scalar will warn of unused var and die because of uninialized variable.
Update++: Questions like this and the explanations from people like danger and tye really are cool. They show the inner workings of Perl and point out the nuances.

Comment on Re: (tye)Re: our/my inconsistency. Download Code

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(tye)Re2: our/my inconsistency. by tye (Sage) on Jan 03, 2001 at 00:03 UTC
`my %hash` does nothing to `%main::hash`, even if you are in `package main`. That is why "package variables" are also called "globals" and "my variables" are called "lexicals". Lexical variables are not in any symbol table. For example: `package one; my $x= "hi"; package two; print "$x\n"; # prints "hi"` [download] This also illustrates a "feature" of our (that might be useful but could also be a source of problems): `package one; our $x= "hi"; use vars qw($y); $y= "lo"; package two; print "$one::x $one::y\n"; # prints "hi lo" print "$x\n"; # prints "hi" print "$y\n"; # prints nothing # and would give an error under C<use strict>` [download] - tye (but my friends call me "Tye")	[reply] [d/l] [select]
Re: Re: (tye)Re: our/my inconsistency. by danger (Priest) on Jan 03, 2001 at 00:00 UTC
Strict means you must declare your variables with my(), our(), or 'use vars', or use fully qualified package names. Using our() or 'use vars' is just a way of saying we want a global variable but we don't want to have to use the fully qualified name all the time -- you do not have to declare globals that way if you do use fully qualified names (as you do in your sub). Your example has two hashes: the global %main::hash (created on the fly in your subroutine) and the lexical %hash (declared near the top with the my() statement). No warnings are produced by your sub because the main::hash is referenced twice (no 'used only once' warning), and the print() never executes because there are no keys to loop over (no 'unitialized' warnings).	[reply]