1 Here are the definitions pre-loaded for working on assignment 3:
3 <textarea id="INPUT" style="border: 2px solid black; color: black; font-family: monospace; height: 3in; overflow: auto; padding: 0.5em; width: 100%;">
6 let and = \l r. l (r true false) false in
7 let makePair = \f s g. g f s in
10 let nil = makePair true meh in
11 let isNil = \x. x fst in
12 let makeList = \h t. makePair false (makePair h t) in
13 let head = \l. isNil l err (l snd fst) in
14 let tail = \l. isNil l err (l snd snd) in
15 let mylist = makeList 1 (makeList 2 (makeList 3 nil)) in
16 let Y = \f. (\h. f (h h)) (\h. f (h h)) in
17 let isZero = \n. n (\x. false) true in
18 let succ = \n s z. s (n s z) in
19 let mult = \m n s. m (n s) in
20 let length = Y (\length l. isNil l 0 (succ (length (tail l)))) in
21 let pred = \n. isZero n 0 (length (tail (n (\p. makeList meh p) nil))) in
22 let leq = \m n. isZero(n pred m) in
23 let eq = \m n. and (leq m n)(leq n m) in
27 <input id="PARSE" value="Normalize" type="button">
28 <input id="ETA" type="checkbox">do eta-reductions too
29 <noscript><p>You may not see it because you have JavaScript turned off. Uffff!</p></noscript>
30 <script src="/code/lambda.js"></script>
31 <script src="/code/tokens.js"></script>
32 <script src="/code/parse.js"></script>
33 <script src="/code/json2.js"></script>
37 /*jslint evil: true */
39 /*members create, error, message, name, prototype, stringify, toSource,
43 /*global JSON, make_parse, parse, source, tree */
45 // Make a new object that inherits members from an existing object.
47 if (typeof Object.create !== 'function') {
48 Object.create = function (o) {
55 // Transform a token object into an exception object and throw it.
57 Object.prototype.error = function (message, t) {
59 t.name = "SyntaxError";
66 var parse = make_parse();
69 var string, tree, expr, eta;
72 // string = JSON.stringify(tree, ['key', 'name', 'message', 'value', 'arity', 'first', 'second', 'third', 'fourth'], 4);
73 expr = tree.handler();
74 // string = JSON.stringify(expr, ['key', 'name', 'message', 'value', 'arity', 'first', 'second', 'tag', 'variable', 'left', 'right', 'bound', 'body' ], 4);
75 // string = expr.to_string() + "\n\n~~>\n\n";
77 eta = document.getElementById('ETA').checked;
78 string = string + reduce(expr, eta, false).to_string();
80 string = JSON.stringify(e, ['name', 'message', 'from', 'to', 'key',
81 'value', 'arity', 'first', 'second', 'third', 'fourth'], 4);
83 document.getElementById('OUTPUT').innerHTML = string
84 .replace(/&/g, '&')
85 .replace(/[<]/g, '<');
88 document.getElementById('PARSE').onclick = function (e) {
89 go(document.getElementById('INPUT').value);