Function overloading: Difference between revisions

Revision as of 12:33, 30 June 2024

Revision as of 05:26, 1 July 2024

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* [[Nim (programming language)|Nim]]<ref>{{cite web|title=Nim Manual|url=https://nim-lang.org/docs/manual.html#overloading-resolution|website=nim-lang.org|language=en}}</ref>

* [[Crystal (programming language)|Crystal]]<ref>{{cite web|title=Crystal Docs|url=https://crystal-lang.org/reference/1.8/syntax_and_semantics/overloading.html|website=crystal-lang.org|language=en}}</ref>

* [[Delphi_Delphi (software)|Delphi]]<ref>{{cite web|title=Embarcadero Delphi|url=https://docwiki.embarcadero.com/RADStudio/Athens/en/Overloading|website=embarcadero.com|language=en}}</ref>

==Rules in function overloading==

* The same function name is used for more than one function definition in a particular module, class or namespace

* The functions must have different [[Typetype signature|type signatures]]s, i.e. differ in the number or the types of their formal parameters (as in C++) or additionally in their return type (as in Ada).<ref>{{cite book

| last1 = Watt

| first1 = David A.

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| publisher = John Wiley & Sons, Inc.

| isbn = 978-0-470-85320-7

| pages = 204-207204–207

}}

</ref>

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The mistake comed from confusion in each form of static polymorphism as following:

* ''[[Parametric polymorphism]]'' differs from overloading by that the function definition exists only ones and this function invoked with parameters of different types which are substituted formal parameter types.

* ''[[Ad hoc polymorphism]]'' is very similar to overloading but it's depends of a language. This classification was introduced by [[Christopher Strachey]] in 1967, but difference is that he applied for compiler specific features which was exists in some programming languages. It was possibly to define in a module only name of a function and have in another module a multiple functions with same name(exact [[Function overloading|function overloading]]) so one module doesn't have access to another module until compiled. Thus was created effect that in first module was used same function for different parameters but it was just a cosmetic effect therefore [[Christopher Strachey]] gave it such special name as "ad hoc". But not any language has same feature, e.g. in [[Java (programming language)|Java]], there is no possibility define such function, similar example in Java can be achieved by using common interface for both modules but interface should have exact function signature thus ''[[Ad hoc polymorphism]]'' can't be applied.

Function overloading differs from forms of [[Polymorphism (computer science)|polymorphism]] where the choice is made at runtime, e.g. through [[virtual function]]s, instead of statically.