can you elaborate on that please?
what else beyond somethig like typedef function|Callable callable; would be needed? (where Callable refers to the class example i made earlier)
do you mean it would not be easy to write tests for the implementation of a callable type? and what is incomplete about callablep()? also the tests?
or do you mean something else? (why should dificulty of writing tests prevent implementation of a feature?)
greetings, martin.