From 1f4f3108441cfd887eb5c9e6ee53a651a80166ea Mon Sep 17 00:00:00 2001 From: Jim Pryor Date: Sat, 16 Oct 2010 14:14:08 -0400 Subject: [PATCH] alternate Y1,Y2 tweak Signed-off-by: Jim Pryor --- hints/assignment_4_hint_3_alternate_1.mdwn | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) diff --git a/hints/assignment_4_hint_3_alternate_1.mdwn b/hints/assignment_4_hint_3_alternate_1.mdwn index c62d620d..dd55e052 100644 --- a/hints/assignment_4_hint_3_alternate_1.mdwn +++ b/hints/assignment_4_hint_3_alternate_1.mdwn @@ -2,22 +2,22 @@ Alternate strategy for Y1, Y2 * This is (in effect) the strategy used by OCaml. The mutually recursive: - let rec - f x = A ; A may refer to f or g - and - g y = B ; B may refer to f or g - in - C + let rec + f x = A ; A may refer to f or g + and + g y = B ; B may refer to f or g + in + C -is implemented using regular, non-mutual recursion, like this (`u` is a variable not occurring free in `A`, `B`, or `C`): + is implemented using regular, non-mutual recursion, like this (`u` is a variable not occurring free in `A`, `B`, or `C`): - let rec u g x = (let f = u g in A) - in let rec g y = (let f = u g in B) - in let f = u g in C + let rec u g x = (let f = u g in A) + in let rec g y = (let f = u g in B) + in let f = u g in C -or, expanded into the form we've been working with: + or, expanded into the form we've been working with: - let u = Y (\u g x. (\f. A) (u g)) in - let g = Y (\g y. (\f. B) (u g)) in - let f = u g + let u = Y (\u g x. (\f. A) (u g)) in + let g = Y (\g y. (\f. B) (u g)) in + let f = u g -- 2.11.0