method overloading and class overriding
posted 23 years ago
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I had a basic doubt...
Why does the runtime behaviour differ in the above 2 cases?
Overriding a method thro' inheritance seems pretty natural to me.
But the behaviour in the other case (method overloading) puzzles me.
Why runtime type does'nt matter there?
Why does the runtime behaviour differ in the above 2 cases?
Overriding a method thro' inheritance seems pretty natural to me.
But the behaviour in the other case (method overloading) puzzles me.
Why runtime type does'nt matter there?
posted 23 years ago
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Short answer: Because the language designer decided to resolve parameter types at compile time.
Longer answer: It would have been possible to resolve parameter types at runtime, but it's a little bit tricky. For example, you can easily get ambigious situations:
having methods with signatures
foo(Object, String)
foo(String, Object)
which one should be called by
foo("string", "string"); ?
The language designer probably thought that it would be better to not let such problems happen at runtime.
BTW, if you need this form of runtime polymorphism, you should take a look at the Visitor Design Pattern aka Double Dispatch.
Longer answer: It would have been possible to resolve parameter types at runtime, but it's a little bit tricky. For example, you can easily get ambigious situations:
having methods with signatures
foo(Object, String)
foo(String, Object)
which one should be called by
foo("string", "string"); ?
The language designer probably thought that it would be better to not let such problems happen at runtime.
BTW, if you need this form of runtime polymorphism, you should take a look at the Visitor Design Pattern aka Double Dispatch.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus
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posted 23 years ago
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thanks, i found an article on multiple dispatch on the web.
BTW, i was wondering if there are languages that support this kind of runtime behaviour?
thanks.
BTW, i was wondering if there are languages that support this kind of runtime behaviour?
thanks.
Originally posted by Ilja Preuss:
BTW, if you need this form of runtime polymorphism, you should take a look at the Visitor Design Pattern aka Double Dispatch.
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