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Re^2: Defining, Testing and Documenting Perl?

by LanX (Cardinal)
on Dec 24, 2019 at 00:41 UTC ( #11110571=note: print w/replies, xml ) Need Help??


in reply to Re: Defining, Testing and Documenting Perl?
in thread Defining, Testing and Documenting Perl?

> mumbles .oO( ties and overloads )

what's your point?

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

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Re^3: Defining, Testing and Documenting Perl?
by tobyink (Canon) on Dec 24, 2019 at 01:13 UTC

    I believe a tied hash can override how it behaves in scalar context, so that an empty hash can return true and a non-empty hash can return false.

    An overloaded object can do various tricky things with regards to how it behaves as a boolean. For example, it could die.

    if ($x || $y) { say "Something was true. What was it?"; say '$x' if $x; say '$y' if $y; } else { say "Neither was true."; }

    It is possible for this to print "Something was true?" but not tell you what was true. This is because $x or $y could be an overloaded object returning true or false at random each time they are checked.

      yeah I already mentioned overload and I have to admit I didn't expect it but Tie::Hash is indeed mentioning a SCALAR method.

      But those edge cases were not my point, because these are backdoors to fake behavior.

      They should nevertheless be mentioned in a footnote and tested properly in an extra script.

      Cheers Rolf
      (addicted to the Perl Programming Language :)
      Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

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