I wanted to ask if I misunderstood following sentences from "Learning Perl" book p.117:

"Now, when Perl evaluates each %hash, there are no more key-value pairs available so each has to return an empty list.‖ The empty list is assigned to ($key, $value), so $key gets undef, and $value also gets undef.

But that hardly matters, because you’re evaluating the whole thing in the conditional expression of the while loop. The value of a list assignment in a scalar context is the number of elements in the source list—in this case, that’s 0. Since 0 is a false value, the while loop is done, and execution continues with the rest of the program."

while ( ($key, $value) = each %hash ) {
  print "$key => $value\n";
}

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In my opinion, after "($key, $value)" are assigned to "()" and list becomes "(undef, undef)", scalar context takes only the last element of the list, that means 2nd "undef". Am I wrong?

use 5.010;

say '[', scalar (3..4), ']';
say '[', scalar (undef, undef), ']';
say '[', scalar (undef, 1, undef, 5), ']';

@a = (3..4);
@b = (undef, undef);
@c = (undef, 1, undef, 5);

say '[', scalar @a, ']';
say '[', scalar @b, ']';
say '[', scalar @c, ']';

say '[', scalar 3..4, ']';

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OUTPUT: 
[]
[]
[5]
[2]
[2]
[4]
[34]

[download]

In reply to each %hash: scalar context of list (undef, undef) is false by rsFalse

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