X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=assignment3.mdwn;h=71960dc8429ebf75a81638f7c6664fe2dfc17c99;hp=d00dba0b2cbbfa44a6adc84668e145aa6e96a7b6;hb=f3400cc9679e5f4f78cee730349d74e465648eac;hpb=97cbee46cb35e1eb7aa5ea5f8b1af3583f5b7522;ds=sidebyside

diff --git a/assignment3.mdwn b/assignment3.mdwn
index d00dba0b..71960dc8 100644
--- a/assignment3.mdwn
+++ b/assignment3.mdwn
@@ -8,7 +8,7 @@ assignment much faster and more secure.
 
 Recall that version 1 style lists are constructed like this:
 
-<textarea id="INPUT" style="border: 2px solid black; color: black; font-family: monospace; height: 3in; overflow: auto; padding: 0.5em; width: 100%;">
+<pre>
 let true = \x y. x in
 let false = \x y. y in
 let makePair = \f s g. g f s in
@@ -25,71 +25,8 @@ let Y = \f. (\h. f (h h)) (\h. f (h h)) in
 let length = Y (\length l. isNil l 0 (succ (length (tail l)))) in
 
 length mylist
-</textarea>
-<input id="PARSE" value="Normalize" type="button">
-<input id="ETA" type="checkbox">do eta-reductions too
-<noscript><p>You may not see it because you have JavaScript turned off. Uffff!</p></noscript>
-<script src="/code/lambda.js"></script>
-<script src="/code/tokens.js"></script>
-<script src="/code/parse.js"></script>
-<script src="/code/json2.js"></script>
-<pre id="OUTPUT">
 </pre>
-<script>
-/*jslint evil: true */
 
-/*members create, error, message, name, prototype, stringify, toSource,
-    toString, write
-*/
+Then `length mylist` evaluates to 3.
 
-/*global JSON, make_parse, parse, source, tree */
-
-// Make a new object that inherits members from an existing object.
-
-if (typeof Object.create !== 'function') {
-    Object.create = function (o) {
-        function F() {}
-        F.prototype = o;
-        return new F();
-    };
-}
-
-// Transform a token object into an exception object and throw it.
-
-Object.prototype.error = function (message, t) {
-    t = t || this;
-    t.name = "SyntaxError";
-    t.message = message;
-    throw t;
-};
-
-
-(function () {
-    var parse = make_parse();
-
-    function go(source) {
-        var string, tree, expr, eta;
-        try {
-            tree = parse(source);
- //           string = JSON.stringify(tree, ['key', 'name', 'message', 'value', 'arity', 'first', 'second', 'third', 'fourth'], 4);
-			expr = tree.handler();
-            // string = JSON.stringify(expr, ['key', 'name', 'message', 'value', 'arity', 'first', 'second', 'tag', 'variable', 'left', 'right', 'bound', 'body' ], 4);
-//			string = expr.to_string() + "\n\n~~>\n\n";
-			string = '';
-			eta = document.getElementById('ETA').checked;
-			string = string + reduce(expr, eta, false).to_string();
-        } catch (e) {
-            string = JSON.stringify(e, ['name', 'message', 'from', 'to', 'key',
-                    'value', 'arity', 'first', 'second', 'third', 'fourth'], 4);
-        }
-        document.getElementById('OUTPUT').innerHTML = string
-            .replace(/&/g, '&amp;')
-            .replace(/[<]/g, '&lt;');
-    }
-
-    document.getElementById('PARSE').onclick = function (e) {
-        go(document.getElementById('INPUT').value);
-    };
-}());
-
-</script>
+What does `head (tail (tail mylist))` evaluate to?