Re: [Cbor] "ordered hash"

[Michael Richardson <[e-mail]>]

Carsten Bormann <[e-mail]> wrote:
    > By using the exact structure of a map (except that the array head will
    > have double the argument that the map head has), we can save 1 byte per
    > k/v pair (“flattened alist”):

    > FAList<K, V> = [* (K, V)]

    > So [[“a”, 1], [“b”, 2]] becomes [“a”, 1, “b”, 2]

    > I’m not sure which of these MCR was inquiring on.  The first is
    > definitely an alist, and there is no need for a new term.  The second
    > can be called an ordered multimap, but there are other structures that
    > also deserve this name.

I am definitely referring to this.
"flattened alist" is a new term to me, and I'm mostly happen with this term.
I am unclear what the "second one" is.

I think that:
 Alist: [[“a”, 1], [“b”, 2]]
 flatened alist: [“a”, 1, “b”, 2]

    > OMList<K, V> = [* (K, [2* V] / V)]

    > So [[“aaa”, 1], [“aaa”, 2], [“bbb”, 3]] becomes [“aaa”, [1, 2], “bbb”, 3]

It's an optimization which is not preserve the order.
That is:
   [[“aaa”, 1], [“aaa”, 2], [“bbb”, 3]]
vs:[[“aaa”, 1], [“bbb”, 3], [“aaa”, 2]]
vs:[[“aaa”, 2], [“bbb”, 3], [“aaa”, 1]]

I agree that a tag may be in order.

--
Michael Richardson <[e-mail]>, Sandelman Software Works
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