'if' as a _function_, in Scheme and Python

Steve Schafer pandeng at telepath.com
Thu Aug 19 20:16:09 EDT 1999


On Thu, 19 Aug 1999 22:31:49 GMT, oleg at pobox.com wrote:

>To show it clearer, let me re-write my-if as
>
>        (define (my-if condition then-branch else-branch)
>           ((cdr (assq (eq? condition #f)
>                (list (cons #t else-branch) (cons #f then-branch))))))
>
>This definition is _purely_ functional

Not only is it purely functional, it also unconditionally evaluates
both branches (in Scheme). Therefore, it is not equivalent to IF.

-Steve





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