topical slide(s): creative technology / new media / game development(s)

Abstract data types -- packages

$x:\E %a.{ val : %a, op : %a -> Int }$
$x = pack[%a = Int in { val:%a, op:%a -> Int } ]((3,S))$
$x.op(x.val) = 4$

Encapsulation

$pack [ representation in interface ]( contents )$

interface -- type $\E %a. { val : %a, op : %a -> Int }$
representation -- $%a = Int$ \zline{(hidden data type)}
contents -- $(3,S)$

slide: Packages -- examples