For Perl 6 we've been promised a "yada yada yada" operator, which makes
'...' valid syntax for "I'll fill this bit in later.", allowing the code
to compile, but issue a run-time warning.

But, like many of the other things that may or may not happen in Perl 6,
we can already make this happen in Perl 5.

All you need is to 'use Yada::Yada::Yada' and off you go ...