DB<114> $h={a=>42}
 => { a => 42 }

  DB<115> "$h->{a}"
 => 42

##</code><code>##

  DB<118> $sub=sub { "nope" }
 => sub { "???" }

  DB<119> "$sub->()"
 => "CODE(0xa5cc200)->()"

##</code><code>##

  DB<120> $_="X"
 => "X"

  DB<121> s/X/@{[ $sub->() ]}/
 => 1

  DB<122> $_
 => "nope"