[racket] Evaluation problem

On Mon, 1 Oct 2012, Mikko Tiihonen wrote:

> [...]
> (define make-pair
>  (lambda (first)
>    (lambda (second)
>      (lambda (func)
>        (func first) second))))
> [...]
> So, select-first returns the correct result when applied directly but 
> returns the second argument when applied via make-pair. Also, I have 
> checked that the implementation of make-pair gives the correct result if 
> I do the beta-reduction by hand.
> [...]

Hello Mikko,

the innermost lambda in make-pair consists of two expressions; it applies 
func to first for side effects and then it always returns second.

Probably you wanted to write
   ((func first) second)
instead of
   (func first) second

Ciao,
Thomas


-- 
When C++ is your hammer, every problem looks like your thumb.
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