Most of the non-running code examples in synopses could be classified as "fill in the blanks" omissions and "assuming an environment" omissions.

For "fill in the blanks", Perl 6's ... (yada yada yada) operator will mostly fix that. This applies generally to higher-order libraries, visitors and event-generators that take callbacks.

For "assuming an environment", it would be more difficult, as you can't really know what environment the author expects of the end-user.

-David