Is it possible to do function overloading in F#?

Question

Hi!

Something like

let f x = log(x)

and later I can apply f to matrix, vector or a float.

I guess it is not possible since F# is strictly static typed. Any other patters to overcome this problem?

Thanks!

Answer 1

You can use operator overloading for types/classes:

type Fraction = 
  { n : int; d : int; }
  static member (+) (f1 : Fraction, f2 : Fraction) =
    { n = f1.n * f2.d + f2.n * f1.d; d = f1.d * f2.d }

or inlined functions:

> let inline fi a b = a+b;;
val inline fi :
   ^a ->  ^b ->  ^c when ( ^a or  ^b) : (static member ( + ) :  ^a *  ^b ->  ^c)

Answer 2

See my answer to this question:

http://stackoverflow.com/questions/501069/f-functions-with-generic-parameter-types

Briefly:

• You can overload members of a class (but not let-bound functions)
• You can use 'inline' and 'hat' types
• You can simulate Haskell type classes and explicitly pass dictionaries-of-methods
• You can use do run-time type tests casting from 'obj'