shift may not be the culprit, if you look at how the assignment is evaluated. Both the scalar and array assignment are evaluated in scalar context

  DB<41> x { $max=100; while (  () = undef  ) {print "$x, "; last if $
+max-- == 0 } }
, , , , , , , , , , , , , , , ... , , , , , , , , , , , , , , , , , , 
+, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,
+ , , , , , , , , , , ,   empty array

DB<42> x { $max=100; while (  $_ = undef  ) {print "$x, "; last if $ma
+x-- == 0 } }
0  undef

[download]

I dont know if this might be affecting how shift is working, but may shed some light.

I did investigate the splice/shift difference a little, they behave the same when both @x and @array are undef, but different when, as you highlighted they are empty.

Possibly shift and splice are optimised at that level due to their expected usage.

Update: this may be something to consider.

  DB<60> x { $max=100; while ( @x = splice( @{[]},0,1 )) {print "$x, "
+; last if $max-- == 0 } }
0  0
DB<61> x { $max=100; while (  @x = shift @{[]}  ) {print "$x, "; last 
+if $max-- == 0 } }
, , , , , , , , , , , , , , ... , , , , , , , , , , , , , , , , , , , 
+, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,
+ , , , , , , ,   empty array

[download]

In reply to Re: shift on empty array in list context broken by Don Coyote
in thread shift on empty array in list context broken by LanX

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