in reply to Re: shift on empty array in list context broken
in thread shift on empty array in list context broken

> they behave the same when both @x and @array are undef,

not sure what you mean here...(?)

anyway I doubt it's possible to "fix" this, much code will rely on shift returning undef.

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

  • Comment on Re^2: shift on empty array in list context broken

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Re^3: shift on empty array in list context broken
by Don Coyote (Hermit) on Jul 16, 2019 at 12:29 UTC

    I'm not exactly sure either. I attempted to write some Test scripts. Getting only as far as comparing a couple of variations.

    heres two scripts that start out looking to compare list and scalar context asignment. I'm not sure they have picked up what you are viewing, but could possibly get there?

    A B my @x @y Scalar Context

    Read more... (3 kB)

    C D my (@x),(@y) List Context

    Read more... (3 kB)
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      well not really short and concise...

      undef is/was IIRC meant to free memory.

      though I can't reproduce any difference between an emptied and destroyed array.

      list context different: 

        DB<49> undef @x

  DB<50> x [ shift @x, splice @x,0,1 ]
0  ARRAY(0x34a5270)
   0  undef
  DB<51> @x=()

  DB<52> x [ shift @x, splice @x,0,1 ]
0  ARRAY(0x34a6c48)
   0  undef
  DB<53>

      [download]

      scalar context same 

        DB<54> undef @x

  DB<55> x [ ($a=shift @x), ($b=splice @x,0,1) ]
0  ARRAY(0x34a6960)
   0  undef
   1  undef
  DB<56> @x=()

  DB<57> x [ ($a=shift @x), ($b=splice @x,0,1) ]
0  ARRAY(0x34a6f18)
   0  undef
   1  undef

      [download]

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

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        I am viewing the docs, x [maxdepth] expr\n\tEvaluates its expression in list context .... Would this affect the interpretation of the contexts?

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