Re: List functions

[Hans Åberg]

On 2 Dec 2010, at 17:06, Hans Aberg wrote:

> Another problem: passing a list of length two to a function that  
> takes two non-arguments. For example,
>  (define h (lambda (x y) (display x) (display y)))
> and passing (list 1 2) to it.
>
> It is in the same context as before: I want to build functions like  
> in Haskell
>  f((1, 2), 3) where f = \((x, y), z) -> (x, y, z)
>  --> (1,2,3)

I found that this is possible by:
  (define f (lambda (a z) (primitive-eval (cons (lambda (x y) (+ x y  
z)) a))))
Then
  (f (list 1 2) 3) --> 6

The primitive "list" is important here, as shown in the examples by  
Keith. So it seems one should type data-lists by adding this symbol.  
But it is not available in the C-interface as symbol, so I added it in  
my interface, and in fact a variation called "tuple", which is the  
same as "list", only that (tuple x) --> x.