> I think `insert' may be a good choice.
> What do you guys think about adding this method to Array?
> And possibly `insert_after' to make emulating `push' easier.

How about a pair insert_before/insert_after. This would take care of
all additions. String(and other Sequence types) could also use them.
 
> 
> In addition, should inserting array be treated specially?  E.g.
> 
>   [1,2,3].insert(0,[5,6])         #=> [[5,6],1,2,3] or [5,6,1,2,3]
> 

How about a pair group_insert_before/group_insert_after which leads to 
the latter. This would save the for loop.

Thanks

-Ted Meng