What's a "Polymorphic method"?

Question

Sometimes people use the phrase "Polymorphic method/function".

Does it mean:

A method that takes a Polymorphic type as a parameter, and performs some operation on it. By "Polymorphic type" I mean a super-type with multiple sub-types.
An abstract or virtual method in a super-type, with multiple sub-types that implement/override the method differently.

I'd say probably 2), but without context it's impossible to say. Who uses the phrase? — Kilian Foth, Commented Aug 16, 2014 at 7:21
It can actually be both things depending on the language, feature and technology used. Runtime polymorphism is based on virtual methods, static polymorphism (like CRTP) is based on template parameters and template functions (something yo ueven don't mention). Some languages distinguish classes and interface, some other don't (and admit abstract mthods to be intermixed with implemented ones) ... — Emilio Garavaglia, Commented Aug 16, 2014 at 7:47
You can also have the case of a method that does the same thing on different types (parametric polymorphism). E.g. in Java a method add on a list will append an object to the list. The type parameter of the list (List<String>, List<Customer>) ensures that an object of the correct class is appended. — Giorgio, Commented Aug 16, 2014 at 8:50

Emilio Garavaglia · Accepted Answer · 2014-08-16 07:58:31Z

2

The therm "polymorphic", alone, means nothing more that "a noun or verb that can act differently depending on context".

You say "do" and something gets done. What is actually done ... depend on the something.

How this translated into programming depends on the chosen language, its features and the way you use those features to manipulate things.

Even C (that's not normally thought as an OOP language) can use a statement like a.(*do)() to do different things depending on a...

answered Aug 16, 2014 at 7:58

Emilio Garavaglia

4,2991 gold badge23 silver badges23 bronze badges

Add a comment |

1 Answer 1