On 12/06/12 19:41, Alan Malloy wrote:
It's not just less convenient, but genuinely incorrect to use dot-
notation for protocol functions. Not every class that satisfies the
protocol will be implementing the interface directly, and so dot-
notation will fail on them. The interface generated by defprotocol
exists primarily to allow the compiler to optimize certain cases, not
because it's an interface your application should be using.
Hmmm...that sort of makes sense but i wasn't planning on implementing
the protocol outside the current namespace - only consuming its
implementors. Perhaps from a java program - that is why I gave java-like
names to my methods and overrode toString from object on my records. The
original confusion arose from the fact that I wanted to pass IPiece as
argument to avoid reflection which is not needed after all!
Within the definition of a record is it again recommended to call
methods without the dot? for example is this completely wrong? (notice
"(.getGridPosition this)" and (.getListPosition this))
(defrecord ChessPiece [^java.awt.Image image
^java.awt.Point position
rank ^Integer value]
Piece
(update-position [this np] ;mutable state inside Point!
(.setLocation position ;can accept ints or doubles
^double (first np) ^double (second np))) ;np should be [x, y]
(die [this] (vary-meta this assoc :dead true)) ;communicate death
through meta-data
(promote [this] (make-chessItem image position :chess? true :rank
'queen)) ;a pawn is promoted to a queen
(getGridPosition [this] (vector (.getX position) (.getY position)))
(getListPosition [this] (translate-position (first (.getGridPosition
this))
(second (.getGridPosition
this)) (chess :mappings)))
(getPoint [this] position)
(getMoves [this] nil) ;TODO
Object
(toString [this]
(println "ChessItem (" rank ") at position:" (.getListPosition this)
" ->" (.getGridPosition this))) )
Thanks everyone for your precious time...
Jim
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