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The need to specify 'rec' in a recursive function defintion

Saptarshi Guha
- Guillaume Yziquel
  - Saptarshi Guha
- Gerd Stolpmann
  - Guillaume Yziquel
    - Gerd Stolpmann
      - Guillaume Yziquel
        
        Alain Frisch
  - Jon Harrop
    - rossberg@m...
  - Saptarshi Guha
  - Andrej Bauer
    - Francois Maurel
    - rossberg@m...
- Jon Harrop
  - Saptarshi Guha
    - Jon Harrop
- Stefan Monnier
  - Till Varoquaux
    - Jon Harrop
    - Stefan Monnier
      - Jon Harrop
        
        Stefan Monnier
        
        Stefan Monnier
        
        Ashish Agarwal

Date:	-- (:)
From:	Francois Maurel <Francois.Maurel@n...>
Subject:	Re: [Caml-list] The need to specify 'rec' in a recursive function defintion

>
>
> # let y = z z ;;
> val y : (('_a -> '_b) -> '_a -> '_b) -> '_a -> '_b = <fun>
>
> Can anyone get rid of the pesky underscores in the type of y above, so
> that it becomes truly polymorphic?
>

Eta expansion does it...

# let y x = z z x;;
val y : (('a -> 'b) -> 'a -> 'b) -> 'a -> 'b = <fun>

Regards,
François