Hi,

small add on to my last mail.

Think of it as having a set of work queues: clean, dirty, reading,
writing, write_prepare. The objects need to be able to quickly jump
from one queue to the back of another when the objects internal state
changes. And is not only the objects at the head of the queue that
change states. Can be pretty random what object changes.

If I put the prev/next links into the objects themself they can easily
detach themself from a queue and insert themself into another.

If I put the objects into other generic queue structures then I have to
find the position in the old queue to remove an object and that would
be slow.


If you can think of a solution that would allow

type 'a data = { next : 'b data option; data : 'a }

without having to know possibly types of 'b then I could use functors.

This would have to work:

let s = { next = None; data = "string" }
let i = { next = Some s; data = 23 }

MfG
        Goswin

PS: and I don't mean using obj.magic. :)