Delegates: Difference between revisions

=={{header|Smalltalk}}==

{{works with|Smalltalk/X}}

Definition of the thingy:

<lang smalltalk>

Object

subclass:#Thingy

instanceVariableNames:''

classVariableNames:''

poolDictionaries:''

thing

^ 'thingy implementation'

</lang>

Definition of the delegator:

<lang smalltalk>

Object

subclass:#Delegator

instanceVariableNames:'delegate'

classVariableNames:''

poolDictionaries:''.

delegate:something

delegate := something

operation

^ delegate

perform:#thing

ifNotUnderstood:'default implementation'.

</lang>

Sample use:

<lang smalltalk>

|d|

d := Delegator new.

d operation.

-> 'default implementation'

d delegate:(Thingy new).

d operation.

-> 'thingy implementation'

</lang>