From: chris Date: Thu, 26 Feb 2015 02:40:39 +0000 (-0500) Subject: (no commit message) X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=commitdiff_plain;h=6d9219c32f63117d5e8dc1d9fc738c56b0cfcff5 --- diff --git a/topics/_week5_system_F.mdwn b/topics/_week5_system_F.mdwn index e69eeb4d..55f49aed 100644 --- a/topics/_week5_system_F.mdwn +++ b/topics/_week5_system_F.mdwn @@ -116,15 +116,15 @@ however. Here is one way, coded in System F|http://www.cis.upenn.edu/~bcpierce/tapl/index.html]] (the relevant evaluator is called "fullpoly"): - N = ∀α. (α->α)->α->α; - Pair = (N->N->N) -> N; - let zero = Λα. λs:α->α . λz:α. z in - let fst = λx:N. λy:N . x in - let snd = λx:N. λy:N . y in - let pair = λx:N. λy:N . λz:N->N->N . z x y in - let suc = λn:N. λα . λlambda s:α->α . λz:α. s (n [α] s z) in - let shift = λp:Pair. pair (suc (p fst)) (p fst) in - let pre = λn:N. n [Pair] shift (pair zero zero) snd in + N = ∀α.(α->α)->α->α; + Pair = (N->N->N)->N; + let zero = Λα.λs:α->α.λz:α. z in + let fst = λx:N.λy:N.x in + let snd = λx:N.λy:N.y in + let pair = λx:N.λy:N.λz:N->N->N.z x y in + let suc = λn:N.λα.λs:α->α.λz:α.s (n [α] s z) in + let shift = λp:Pair.pair (suc (p fst)) (p fst) in + let pre = λn:N.n [Pair] shift (pair zero zero) snd in pre (suc (suc (suc zero)));