curry.p6

sub print ($a, $b = False) {
  # uncommenting this takes the runtime from 0.15s to 0.6s
  #my &reprint = &print.assuming(*, $b);
  given $a {
    when Array {
      '[' ~ join(',', $a.map({ print($_) })) ~ ']';
    }
    when Hash {
      '{' ~ $a.map({.key ~ print(.value)}) ~ '}'
    }
    default { $a.gist }
  }
}

say print { foo => 'bar', baz => ['bla','sdf', {a => 'b', c => ['z']}]};