at:tutorial:objects
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at:tutorial:objects [2007/06/29 14:31] – jorge | at:tutorial:objects [2007/07/02 14:16] – jorge | ||
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Every object understands the message '' | Every object understands the message '' | ||
+ | |||
+ | AmbientTalk also provides a '' | ||
+ | |||
+ | < | ||
+ | > def clonedPoint := clone: point | ||
+ | </ | ||
===== Delegation and cloning ===== | ===== Delegation and cloning ===== | ||
- | AmbientTalk features object inheritance or delegation. By means of delegation, an object can reuse and extend the defintion of another establishing a parent-child relationship. We identify two kinds of delegation relationships: | + | AmbientTalk features object inheritance or delegation. By means of delegation, an object can reuse and extend the defintion of another establishing a parent-child relationship. We identify two kinds of delegation relationships: |
+ | |||
+ | |||
+ | {{: | ||
The following code shows how to extend objects with a **IS-A** relationship. It uses the '' | The following code shows how to extend objects with a **IS-A** relationship. It uses the '' | ||
Line 57: | Line 67: | ||
> def point3D := extend: point with: { | > def point3D := extend: point with: { | ||
def z := 0; | def z := 0; | ||
- | def sumofsquares() { | + | def sumOfSquares() { |
- | super.sumofsquares() + z*z | + | super^sumOfSquares() + z*z |
} | } | ||
} | } | ||
Line 68: | Line 78: | ||
> def point3D := share: point with: { | > def point3D := share: point with: { | ||
def z := 0; | def z := 0; | ||
- | def sumofsquares() { | + | def sumOfSquares() { |
- | super.sumofsquares() + z*z | + | super^sumOfSquares() + z*z |
} | } | ||
} | } | ||
Line 78: | Line 88: | ||
< | < | ||
- | > def OpenConnection | + | > def openConnection |
- | def ClosedConnection | + | > def closedConnection |
- | def Connection | + | > def connection |
- | def open() { | + | def open() { |
- | super := OpenConnection.new(); | + | super := openConnection.new(); |
}; | }; | ||
def close() { | def close() { | ||
- | super := ClosedConnection.new(); | + | super := closedConnection.new(); |
}; | }; | ||
} | } | ||
</ | </ | ||
- | ===== First-class | + | <note important> |
+ | In AmbientTalk, | ||
+ | </ | ||
+ | |||
+ | ===== First-class | ||
+ | AmbientTalk provides an explicit delegation operator '' | ||
+ | |||
+ | < | ||
+ | > def point3D := extend: point with: { | ||
+ | def z := 0; | ||
+ | def init(aX, aY, aZ) { | ||
+ | super^init(aX, | ||
+ | z := aZ; | ||
+ | }; | ||
+ | } | ||
+ | </ | ||
+ | |||
+ | A message sent to an object using the '' | ||
===== Encapsulation ===== | ===== Encapsulation ===== | ||
+ | In AmbientTalk, | ||
+ | < | ||
+ | > def makeObject(hidden) { | ||
+ | object: { | ||
+ | def foo() { /* use hidden */ } | ||
+ | } | ||
+ | } | ||
+ | </ | ||
+ | |||
+ | Due to the encapsulation of this object the following instruction fails: | ||
+ | |||
+ | < | ||
+ | > makeObject(5).hidden; | ||
+ | >> | ||
+ | < | ||
+ | </ |
at/tutorial/objects.txt · Last modified: 2013/05/17 20:23 by tvcutsem