[grandempire]

I know that. But that’s still a different interface. If you have a predicate you now have to wrap that in a different closure that conforms it to a new pattern.

This is the same argument as why have count_if if I can write a for loop.

[Sharlin]

Sure. But at least I interpreted the GP as just saying that the "count-if" operation can be implemented in terms of `reduce` if the latter is available.