30 lines
555 B
Text
30 lines
555 B
Text
(class +Delegator)
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# delegate
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(dm operation> ()
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(if (: delegate)
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(thing> @)
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"default implementation" ) )
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(class +Delegate)
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# thing
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(dm T (Msg)
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(=: thing Msg) )
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(dm thing> ()
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(: thing) )
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(let A (new '(+Delegator))
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# Without a delegate
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(println (operation> A))
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# With delegate that does not implement 'thing>'
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(put A 'delegate (new '(+Delegate)))
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(println (operation> A))
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# With delegate that implements 'thing>'
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(put A 'delegate (new '(+Delegate) "delegate implementation"))
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(println (operation> A)) )
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