Jon, you beat me to it. I was going to mention Ponder.
But Ponder did have a builtin type, it had the function type built in. :)
-- Lennart
On Tue, Nov 2, 2010 at 9:47 PM, Jon Fairbairn
<jon.fairba...@cl.cam.ac.uk> wrote:
> Andrew Coppin <andrewcop...@btinternet.com> writes:
>
>> The other day, I accidentally came up with this:
>>
>> |{-# LANGUAGE RankNTypes #-}
>>
>> type Either x y= forall r. (x -> r) -> (y -> r) -> r
>>
>> left :: x -> Either x y
>> left x f g= f x
>>
>> right :: y -> Either x y
>> right y f g= g y
>>
>> |
>>
>> This is one example; it seems that just about any algebraic
>> type can be encoded this way. I presume that somebody else
>> has thought of this before. Does it have a name?
>
> You could try reading my PhD thesis!
> <http://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-75.html>
> contains a link to the full text scanned to a pdf. (That -- 1985
> -- was a long time ago. One thing I really regret about it is
> that there should have been a comma between "simple" and "typed"
> in the title. I suspect people think "simply typed" when they
> see it). It isn't hard to read (one of my examiners said it made
> good bed-time reading).
>
> Anyway, the relevant part is that Ponder was a programming
> language (Stuart Wray even wrote a GUI programme in it) that had
> (in principle) no built-in types, relying on the type system
> being powerful enough to express anything and the optimiser
> being good enough to convert them to something more sensible.
> In practice neither was /quite/ true, but it got quite close.
>
> --
> Jón Fairbairn jon.fairba...@cl.cam.ac.uk
> http://www.chaos.org.uk/~jf/Stuff-I-dont-want.html (updated 2010-09-14)
>
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe@haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe
>
_______________________________________________
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
