X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=assignment_3_evaluator.mdwn;h=496003d08e11017e54aa4324e7f04a521ce2a60b;hp=9207c05882b63abc88b11ba0716e3487e6e509d6;hb=43a168d149dd549338cd3f8b59c85bef3ba4de20;hpb=aa056fb83840d1a281992dc6e7db351cc513e681

diff --git a/assignment_3_evaluator.mdwn b/assignment_3_evaluator.mdwn
index 9207c058..496003d0 100644
--- a/assignment_3_evaluator.mdwn
+++ b/assignment_3_evaluator.mdwn
@@ -6,17 +6,17 @@ let true = \x y. x in
 let false = \x y. y in
 let and = \l r. l (r true false) false in
 let make\_pair = \f s g. g f s in
-let fst = true in
-let snd = false in
+let get\_fst = true in
+let get\_snd = false in
 let empty = make\_pair true junk in
-let isempty = \x. x fst in
+let isempty = \x. x get\_fst in
 let make\_list = \h t. make\_pair false (make\_pair h t) in
-let head = \l. isempty l err (l snd fst) in
-let tail = \l. isempty l err (l snd snd) in
-
+let head = \l. isempty l err (l get\_snd get\_fst) in
+let tail = \l. isempty l err (l get\_snd get\_snd) in
+;
 ; a list of numbers to experiment on
 let mylist = make\_list 1 (make\_list 2 (make\_list 3 empty)) in
-
+;
 ; church numerals
 let iszero = \n. n (\x. false) true in
 let succ = \n s z. s (n s z) in
@@ -24,20 +24,22 @@ let mul = \m n s. m (n s) in
 let pred = \n. iszero n 0 (length (tail (n (\p. make\_list junk p) empty))) in
 let leq = \m n. iszero(n pred m) in
 let eq = \m n. and (leq m n)(leq n m) in
-
+;
 ; a fixed-point combinator for defining recursive functions
 let Y = \f. (\h. f (h h)) (\h. f (h h)) in
-
+;
 let length = Y (\length l. isempty l 0 (succ (length (tail l)))) in
-
+;
 ; synonyms
 let makePair = make\_pair in
+let fst = get\_fst in
+let snd = get\_snd in
 let nil = empty in
 let isNil = isempty in
 let makeList = make\_list in
 let isZero = iszero in
 let mult = mul in
-
+;
 length (tail mylist)
 </textarea>