Polymorphic copy: Difference between revisions
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package Base is |
package Base is |
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type T is tagged null record; |
type T is tagged null record; |
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type T_ptr is access all T'Class; |
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function Name (X : T) return String; |
function Name (X : T) return String; |
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end Base; |
end Base; |
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begin |
begin |
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Put_Line ("Copied " & Duplicate.Name); -- Check the copy |
Put_Line ("Copied " & Duplicate.Name); -- Check the copy |
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end Copier; |
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-- The function knows nothing about S and creates a copy on the heap |
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function Clone (X : T'Class) return T_ptr is |
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begin |
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return new T'Class(X); |
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end Copier; |
end Copier; |
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Object_1 : T; |
Object_1 : T; |
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Object_2 : S; |
Object_2 : S; |
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Object_3 : T_ptr := Clone(T); |
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Object_4 : T_ptr := Clone(S); |
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begin |
begin |
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Copier (Object_1); |
Copier (Object_1); |
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Copier (Object_2); |
Copier (Object_2); |
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Put_Line ("Cloned " & Object_3.all.Name); |
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Put_Line ("Cloned " & Object_4.all.Name); |
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end Test_Polymorphic_Copy;</lang> |
end Test_Polymorphic_Copy;</lang> |
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The procedure Copier does not know the specific type of its argument. Nevertheless it creates an object Duplicate of exactly same type. Sample output: |
The procedure Copier does not know the specific type of its argument. Nevertheless it creates an object Duplicate of exactly same type. Sample output: |
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Copied T |
Copied T |
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Copied S |
Copied S |
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Cloned T |
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Cloned S |
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</pre> |
</pre> |
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=={{header|Aikido}}== |
=={{header|Aikido}}== |
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Aikido has a native <code>clone</code> function that creates a (deep or shallow) clone of any variable of any type. |
Aikido has a native <code>clone</code> function that creates a (deep or shallow) clone of any variable of any type. |
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