Re: private and limited private

[je@bton.ac.uk (John English)]

Samuel Mize (smize@imagin.net) wrote:
: [... snip ...]

: However, you can still copy it, and use the built-in equality test.
: This is generally OK.  For instance, if you are representing playing
: cards, the type might be a record with two fields, one for suit and
: one for value.  It makes sense to be able to copy a card value (e.g.,
: for the program to remember what card was previously dealt), and to
: compare two values to see if they refer to the same card.

Actually, playing cards would be better represented by a limited type
with a Move (as opposed to a Copy) primitive, since in the real world
you move cards from A to B, you don't *copy* them.  If you allow
assignment, you allow the creation of as many copies of the Ace of
Spades (or whatever) that you like.  From watching Westerns, I gather
that most people frown on this and fill you with lead/break tables
over your head/whatever if you're caught doing it.

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 John English              | mailto:je@brighton.ac.uk
 Senior Lecturer           | http://www.comp.it.bton.ac.uk/je
 Dept. of Computing        | fax: (+44) 1273 642405
 University of Brighton    |
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