From: "Shot (Piotr Szotkowski)" <shot@...>
Date: 2007-01-24T20:41:48+09:00
Subject: Re: a Hash and a Set (sitting in a tree)

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Thanks a lot for your reply, Robert!

Robert Klemme:

> Initially I would defer considerations of performance. I'd start with
> the cleanest design. At the moment I don't have any clue as to what
> processing you are doing so that would probably determine how I would
> set up classes.

Mostly basic set operations on the blocks; Set#&, Set#|,
Set#- and Set#^ seem to cover quite a lot of the base.

> The most straightforward way would probably be to have a BaseBlanket,
> an EncodedBlanket, a PlainBlanket (unencoded) and a Block.

With this approach (i.e., moving the encoding information to the blanket
level, which actually makes sense) Block would be just a Set, nothing
more.

> Whether the BaseBlanket makes sense is probably determined by how much
> an EncodedBlanket and a PlainBlanket have in common, i.e. how much
> functionality they share. That then would go into the BaseBlanket.

In theory, EncodedBlanket is just a Blanket with its blocks named,
so a Blanket class with an EncodedBlanket subclass should cover it.

The catch is, an unencoded blanket can be represented as a Set of
blocks, while and encoded blanket can=E2=80=99t; conversely, an encoded bla=
nket
can be represented as a Hash of (encoding =3D> block) pairs, while an
unencoded blanket can=E2=80=99t.

Maybe I should go with a single Blanket class with an Array of blocks
and a =E2=80=98synchronised=E2=80=99 Array of encodings that would simply b=
e nil for
unencoded blankets? I don=E2=80=99t need the ordering Array would bring in,
but a common class for un- and encoded blankets would simplify things
greatly.

-- Shot
--=20
May the --force be with you.   -- <[tafkam]>

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