Continuations. While most solutions won't need these, those that do need them.
Well, since you brought up continuations, another item I feel like adding to my randomly selected list amongst the many randomly selectable ones is 'hypotheticals'. Perl6-ese for
local is
temp, so far nothing new. But there will be
let as well, and it will behave like
temp except that the value of the variable at the exit of scope will be retained or discarded in favour of the previous one according a condition. I'm not really sure about the exact syntax/semantics, sounds interesting though!!
Perl will compile to Parrot opcodes.
That last is the most important item. This means that any two languages that compile to Parrot will be able to use each other's code seamlessly.
Not only!! It seems that Parrot will indeed be able to run
natively bytecode for other virtual machines (this is rumored to be a side effect of the planned compatibility with a game-oriented VM).