"Gavin Sinclair" <gsinclair / soyabean.com.au> wrote in message
> #any? and #all? are methods of Enumerable, not Array.

Ah yes.

So now I think
   #one, #one?, #none, #none?, #any, #any?, #all, #all?
can all be on Enumerable, perhaps with overrides for Array.

> I like the idea
> of Enumerable#one? and Enumerable#none? to complement them.

I agree.

> But I don't think Enumerable#one? and Array#one are complementary;
> they seem entirely different.

Array#one {|x| pred} would complement Enumerable#one? {|x| pred}
so
Array#one
    is same as Array#one{|x|true}
    which complements Enumerable#one?{|x|true}

> Likewise with Array#any: it's useful, but really has nothing to do
> with #any?

Array#any{|x| pred} complements Enumerable#any? {|x| pred}
so
Array#any complements Enumerable#any?{|x|true}