use Perl

• Another gotcha for you (Score:1)

  by btilly (5037)

  
$ perl -wle 'package foo; our $_; print map {$_} 1..5'
Use of uninitialized value in print at -e line 1.
Use of uninitialized value in print at -e line 1.
Use of uninitialized value in print at -e line 1.
Use of uninitialized value in print at -e line 1.
Use of uninitialized value in print at -e line 1.

  What happened? Well $_ is supposed to be $main::_. But after the our, $_ is now looking at $foo::_ while map still populates $main::_.
  
  You may find http://www.perlmonks.org/?node_id=48379 [perlmonks.org] to be of interest as wel
• Sooo.... (Score:1)

  by Alias (5735)

  So it would be a flaw in a Perl file, if it contains multiple packages, with our statements in them... or at least a critic-worthy warning?
  • Re: (Score:1)

    by chromatic (983)

    File-scoped our variables could be a problem. Block-scoped our variables are less troublesome.
• Yet another gotcha (Score:1)

  by Maddingue (5320)

  Another small problem with our variables is that they take twice the memory of lexical variables or plain global.

  --
  Close the world. txEn eht nepO
  • Re: (Score:1)

    by kwilliams (1467)

    That comment is a bit misleading; if you have a 1000-byte string in an our variable it's not suddenly going to consume 2000 bytes. It would be more accurate to say they take twice the overhead.
• Lexical alias (Score:2)

  by Juerd (1796)

  So in short: "our" creates a lexically scoped alias for a package global variable. And lexical scope itself has nothing to do with packages, but with curlies and files.