Talk:Fixed-point combinator: Difference between revisions

Revision as of 22:44, 27 March 2009

Revision as of 04:18, 28 March 2009

Line 49:

: f is a little too simple, it doesn't have an iterative structure. Let

plus x 1 = suc(x)

plus x 0 = x

plus x y = plus (suc x) (dec y)

: where suc(x) is essentially x+1 and dec y is essentially y -1. Your f is just f = (flip plus 1).

: OK now the problem is plus is defined recursively. So lets make it a function of 3 variables:

plus' g x 1 = suc(x)

plus' g x 0 = x

plus' g x y = g (suc x) (dec y)