Any CodeRef scalar sub truth $b->($a)
Hash Hash hash keys identical [sort keys %$a]~~[sort keys %$b]
- Array Hash hash slice existence grep $_ ~~ $b, @$a
+ Array Hash hash slice existence grep { exists $b->{$_} } @$a
Regex Hash hash key grep grep /$a/, keys %$b
undef Hash always false (undef can't be a key)
Any Hash hash entry existence exists $b->{$a}
+ Hash Array hash slice existence grep { exists $a->{$_} } @$b
Array Array arrays are comparable[2]
+ Regex Array array grep grep /$a/, @$b
+ undef Array array contains undef grep !defined, @$b
Any Array match against an array element[3]
- grep $_ ~~ $a, @$b
+ grep $a ~~ $_, @$b
Hash Regex hash key grep grep /$b/, keys %$a
Array Regex array grep grep /$b/, @$a