use Perl

• Feature (Score:2)

  by davorg (18)

  See also

  $ perl -wle'print $|++ for 1 .. 10'     
  0
  1
  1
  1
  1
  1
  1
  1
  1
  1

  $| only has two values, 0 and 1. I thought this was documented in perlvar but it doesn't seem to be. Perhaps it should be.
  • Re:Feature (Score:2)

    by KM (4)

    Yes, it has a range of [0,1], so I would expect it to stay at 1 when continually incremented. I don't, however, expect it to be incremented to 1 when it is 0 and decremented. I expect:

    0 -> 1 when $|++
    1 -> 1 when $|++
    1 -> 0 when $|--
    0 -> 0 when $|--

    I think the range should be documented, but is it going from a value of 0 to 1 when decremented a bug, or is it a documentation issue? (Of course, once you document a bug is a feature, it isn't a bug anymore :)
    • Re:Feature (Score:2)

      by davorg (18)

      I suppose that as it's a boolean value, then the -1 gets mapped to "true" - or 1. Not sure how intuitive that is tho'.

      Of course, if you ever needed a flip-flop variable then you could make use of this behaviour :)

      $ perl -wle'print $|-- for 1 .. 10'
      0
      1
      0
      1
      0
      1
      0
      1
      0
      1
      • Re:Feature (Score:2)

        by KM (4) on 2002.08.20 8:56 (#11980) Journal

        Yeah, I don't think it is intuitive. I guess it should just be documented somewhere that this is the case with Perl's special boolean vars. I don't like it though, it isn't DWIM.

        Reply to This

        Parent