Is a number divisible by each of its digits?
Perl 6, 13

sub golf($_) {
   $_%%.comb.all
}


Uses the implicit variable $_ — $_ %% .comb.all is equivalent to $_ %% all($_.comb). %% is the "is divisible" operator, and comb with no additional argument returns a list of the characters in a string. As an example, if the argument is 123, then the function evaluates

123 %% all(123.comb)


which is

123 %% all(1, 2, 3)


junction autothreading makes it

all(123 %% 1, 123 %% 2, 123 %% 3)


which is

all(True, False, True)


which is false in boolean context because it's an "all" junction and clearly not all of its elements are true.

It should be possible to coerce the return value to Bool and hide the junction-ness from callers by making the function signature sub golf($_ --&gt; Bool()), but coercions in function signatures don't work yet in Rakudo. The return value is still correctly true or false, it's just not True or False.