my( $a, $b ) = ( shift @as, shift @bs );

[download]

There are lots of constructs where returning an empty list can be surprising if one expects a scalar to be returned.

splice returns a list and so should certainly return an empty list for edge/failure cases. Going back in time, I could see defining shift as returning either 1 scalar or returning the empty list, making that expectation clear, and that decision being a fine one. But I also can see sanity in defining shift as returning a scalar (the current reality).

Consider the relative difficulty of fixing your problem case vs. my counter-factual problem case: 

while( ($x) = shift @a ) {    # Broken
while(  $x  = shift @a ) {    # Fixed
while( @a ) {
    $x = shift @a;            # Better

my( $a, $b ) = ( shift @as, shift @bs );
my( $a, $b ) = ( scalar shift @as, scalar shift @bs );

[download]

Also, consider how likely one is to notice the breakage between the two scenarios.

This leads me to currently slightly prefer the definition of shift as "returns a scalar", that is, the status quo.

- tye        

In reply to Re: shift in list context buggy? (scalar) by tye
in thread shift in list context buggy? by LanX

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