Add a variable to a class instance at runtime: Difference between revisions
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(→{{header|Smalltalk}}: commented the wrong example (long time passed since and original author did not care)) |
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p z. |
p z. |
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p z:40. |
p z:40. |
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p inspect |
p inspect. "shows 3 slots" |
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"Point class is unaffected:" |
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p2 := Point x>20 y:30. |
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p2 z:40. -> error; Point does not implement z: |
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p2 inspect. "shows 2 slots" |
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"but we can create another instance of the enhanced point (even though its an anon class)" |
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p3 := p class new. |
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p3 x:1 y:2. |
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p3 z:4. |
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p3 inspect. "shows 3 slots" |
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</lang> |
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<!-- |
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{{incorrect|Smalltalk|It extends the class (adds a new instance var and new method that will exists even in brand new future instances of that class), not only the particular instance. -- The description of the problem must be reworded then, as it |
{{incorrect|Smalltalk|It extends the class (adds a new instance var and new method that will exists even in brand new future instances of that class), not only the particular instance. -- The description of the problem must be reworded then, as it |
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asks for adding variables to the class, not the instance. |
asks for adding variables to the class, not the instance. |
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CG: commented the bad example; maybe the original author wants to fix it / comment on it. |
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CG: that comment refers to the Monkey code below - not the addSlot example. |
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<lang smalltalk>Object subclass: #Monkey |
<lang smalltalk>Object subclass: #Monkey |
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x: 10 |
x: 10 |
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10</pre> |
10</pre> |
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--> |
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=={{header|Swift}}== |
=={{header|Swift}}== |
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