use Perl

• Example of why this is hard (Score:1)

  by Limbic Region (3985)

  For the benefit of others reading your journal that don't fully understand why this is probably not an easy thing to do....

  sub double { 2 * $_[0] }

  Seems straight forward enough and shouldn't have any side effects. Hrm, what if $_[0] is an alias to a tied variable. What if the FETCH method of that variable has action at a distance. Can't tell just by looking at the source :-(
  • Re:Example of why this is hard (Score:1)

    by DAxelrod (4649) on 2006.10.25 15:57 (#51268) Journal

    It also ocurrs to me that the tainting infrastructure might be useful to look at, because it's another example of looking at how operations propagate properties. Althought it most likely operates at the wrong level of abstraction.

    Reply to This

    Parent

    • Re: (Score:1)

      by jjore (6662)

      FYI, Tainting is a property of values, not code.
      • Re: (Score:1)

        by DAxelrod (4649)

        I realize that. What I was proposing is that we already have a mechanism for determining which expressions propagate taintedness. I was thinking of something that, once data that was a result of a side effect was used, you might be able to use the same mechanism to determine what code was dependent on that side effect.
        
        Then again, I need to brush up on my internals knowledge before I make any more pi-in-the-sky proposals. :)