Inheritance/Single: Difference between revisions
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→{{header|Lua}}: added Lua solution |
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:- end_object.</lang> |
:- end_object.</lang> |
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=={{header|Lua}}== |
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Lua has no in-built formal OOP mechanism, though there are many possible ways of implementing work-alikes. |
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<lang lua>Class = { |
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classname = "Class aka Object aka Root-Of-Tree", |
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new = function(s,t) |
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s.__index = s |
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local instance = setmetatable(t or {}, s) |
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instance.parent = s |
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return instance |
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end |
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} |
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Animal = Class:new{classname="Animal", speak=function(s) return s.voice or "("..s.classname.." has no voice)" end } |
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Cat = Animal:new{classname="Cat", voice="meow"} |
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Dog = Animal:new{classname="Dog", voice="woof"} |
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Lab = Dog:new{classname="Lab", voice="bark"} |
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Collie = Dog:new{classname="Collie"} -- subclass without a unique voice |
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print("Animal:speak(): " .. Animal:speak()) |
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print("Cat:speak(): " .. Cat:speak()) |
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print("Dog:speak(): " .. Dog:speak()) |
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print("Lab:speak(): " .. Lab:speak()) |
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print("Collie:speak(): " .. Collie:speak()) |
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max = Collie:new{voice="Hi, I am Max the talking Collie!"} -- instance with a unique voice |
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print("max:speak(): " .. max:speak()) |
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print("max himself is (instance): " .. max.classname) |
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print("max's parent is (class): " .. max.parent.classname) |
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print("max's parent's parent is (class): " .. max.parent.parent.classname) |
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print("max's parent's parent's parent is (class): " .. max.parent.parent.parent.classname) |
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print("max's parent's parent's parent's parent is (class): " .. max.parent.parent.parent.parent.classname) |
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print("max's parent's parent's parent's parent's parent is (nil reference): " .. tostring(max.parent.parent.parent.parent.parent))</lang> |
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{{out}} |
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<pre>Animal:speak(): (Animal has no voice) |
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Cat:speak(): meow |
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Dog:speak(): woof |
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Lab:speak(): bark |
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Collie:speak(): woof |
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max:speak(): Hi, I am Max the talking Collie! |
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max himself is (instance): Collie |
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max's parent is (class): Collie |
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max's parent's parent is (class): Dog |
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max's parent's parent's parent is (class): Animal |
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max's parent's parent's parent's parent is (class): Class aka Object aka Root-Of-Tree |
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max's parent's parent's parent's parent's parent is (nil reference): nil</pre> |
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=={{header|M2000 Interpreter}}== |
=={{header|M2000 Interpreter}}== |