[ruby-talk:5652] Array#insert

I was looking up how Array#insert should be called. Uh, there's none! Maybe
there's some other suitable method somewhere in the middle of the other, but
I didn't spot it fast.

Of course ary[index,0] = stuff. But it's very annoying format, when you
could be more explicit too. Besides there's always the surprise of

  ruby -e'a=[1,2,3]; a[1,0]=[4,5]; p a;'
  [1, 4, 5, 2, 3]
  ruby -e'a=[1,2,3]; a[1,0]=[[4,5]]; p a;'
  [1, [4, 5], 2, 3]

lurking, and I'd expect the first example output what the second does.

If there should be Array#insert we should probably make up our mind whether
it should be implemented as (not any real code, just to show possible few
points for debate)

  class Array
    def insert(index, *ary)
      self[index<+1>, 0] = <*>ary
    end
  end

where <+1> is about having semantics of "insert-before/at" or "insert-after"
index, and <*> if there should be some sort of autoflattening, or in some
other form. I personally don't have opinion should the semantics be before
or after, but I'd expect Array#insert not to autoflatten in any way.

	- Aleksi