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Re^2: Variable assignment error checking

by greengaroo (Hermit)
on Dec 15, 2013 at 02:45 UTC ( #1067203=note: print w/ replies, xml ) Need Help??


in reply to Re: Variable assignment error checking
in thread Variable assignment error checking

davido has the answer. That's the way to do it. If func returns 0 or undef, $var will be assigned to $var, therefore keeping its original value. I use this technique all the time.

A for will get you from A to Z; a while will get you everywhere.


Comment on Re^2: Variable assignment error checking
Re^3: Variable assignment error checking
by Anonymous Monk on Dec 15, 2013 at 06:39 UTC
    $cough ||= cough( $cough );
      Call the function cough($cough) only if $cough is true?

      The OP requested to assign the return value of func($var) if that return value is true. Otherwise, to hold the original value of $var.

      You coughed up this: If $var is true, keep it, otherwise store a return value from func($var).

      To put it another way: Specification: if the function returns a true value, store it. Otherwise keep the original value.

      Your solution: If the original value is true keep it, otherwise call the function and keep its return value instead.

      Inverted logic. But you're not alone; several people upvoted your post, so it must be an easy mistake to make.


      Dave

        ... Inverted logic. But you're not alone; several people upvoted your post, so it must be an easy mistake to make.

        This :) When brain function less (like sleep deprivation), pattern recognition takes place instead of logic processing ... and  $foo = bar($foo) || $foo; is so close to  $foo = $foo || bar($foo); the association to  $foo ||= bar( $foo ); happens, and tired brain fail to realize they're different

        human brains, what can I tell you :)

        hmm, its more like logic processing doesn't check pattern recognition ... argument validation, even for brains

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