This seems to be a bug in Data::Dumper. With the perl debugger (before the grep, thanks tye):

main::(-:1):    my @matrix = ();
  DB<1> n
main::(-:2):    $matrix[2]->[3] = "What's goin' on?";
  DB<1> n
main::(-:3):    grep {/Huh?/}@$_ for @matrix;
  DB<1> print @matrix
ARRAY(0x8103f2c)
  DB<2> x @matrix
0  undef
1  undef
2  ARRAY(0x8103f2c)
   0  empty slot
   1  empty slot
   2  empty slot
   3  'What\'s goin\' on?'
  DB<3>

[download]

With Data::Denter:

Before grep:
@
    ?
    ?
    @
        ?
        ?
        ?
        What's goin on?

After grep:
@
    @
    @
    @
        ?
        ?
        ?
        What's goin on?

[download]

... indicating undef (?) before the grep, as normal, and empty array refs (@) after the grep, as normal due to autovivification upon array dereference. Only Data::Dumper seems to get it wrong, or at least what seems to be wrong.

In reply to Re: A new perl {cough} feature? by premchai21
in thread A new perl {cough} feature? by tachyon

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