Functor

1 definition found

From The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]:

  functor
       
          In {category theory}, a functor F is an operator on types.  F
          is also considered to be a {polymorphic} operator on functions
          with the type
       


          	F : (a -> b) -> (F a -> F b).
       
          Functors are a generalisation of the function "{map}".  The
          type operator in this case takes a type T and returns type
          "list of T".  The map function takes a function and applies it
          to each element of a list.
       
          (1995-02-07)