Conditionals are not always evaluated. The compiler can sometimes decide to phrase things differently. 
U:\> perl -MO=Deparse -le "$x = 5; if ($x) { print $x }"
$x = 5;
if ($x) {
    print $x;
}

[download]
U:\>perl -MO=Deparse -le "$x = 5; if (0) { print $x }"
$x = 5;
'???';

[download]
U:\>perl -MO=Deparse -le "$x = 5; if (1) { print $x }"
$x = 5;
print $x;;

[download]
U:\>perl -MO=Deparse -le "$x = 5; if (! 0) { print $x }"
$x = 5;
print $x;;

[download]

--
[ e d @ h a l l e y . c c ]

In reply to Re^4: unless versus if ( ! ) inside a subroutine by halley
in thread unless versus if ( ! ) inside a subroutine by Wheeler

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