Re^3: Conditional initialization of my-variables

[eyepopslikeamosquito]

Bod, I suggest you consider dropping your "major exception" in favour of LanX's excellent advice. That is, I prefer LanX's:

$input //= 1;  # default if undefined

to your:

$input = 1 unless defined $input;

See also:

• Set default values with the defined-or operator (Effective Perler)
• How to set default values in Perl (perlmaven)
• Perl Best Practices (reserve postfix if for flow-of-control)

[LanX]

> How to set default values in Perl

Gabor is mixing two cases in his article,

• defaulting undef values
• defaulting missing values (like with the hashes)
But doesn't give an example for missing values in arrays.

TIMTOWTDI, alas not very DRY

  DB<30> x @_
0  1
1  2
  DB<31> x ($a,$b,$c,$d) = (@_, ("D1".."D4")[@_..3])
0  1
1  2
2  'D3'
3  'D4'
  DB<32>

or

  DB<32> @DEF= ("D1".."D4")

  DB<33> x ($a,$b,$c,$d) = (@_, @DEF[@_..$#DEF])
0  1
1  2
2  'D3'
3  'D4'
  DB<34>

edit

or

use v5.12.0;
use warnings;
use Data::Dump qw/pp dd/;


sub test {
    my ($x, $y, $z) =
      ( @_,
        ("X","Y","Z")[@_..42]
      );

    pp ($x, $y, $z);
}

test(1..$_) for 0..3

-->

("X", "Y", "Z")
(1, "Y", "Z")
(1, 2, "Z")
(1, 2, 3)