nothing

[Rod Adams]

Does Perl need a no-op function?
With the addition of "no bare literals", it makes constructs like
1 while some_func();
an error. I propose creating a no-op function "nothing" that can be used 
here or anywhere else you specifically wish to do nothing at all.

 given $this {
   when Even  { nothing };
   when Prime { ... };
   default    { ... };
 }
As a side question, I assume that there's a predicate form of "when", 
but it's not mentioned.

 given $this {
   nothing when Even;
   when Prime { ... };
   default    { ... };
 }
-- Rod Adams