X-Git-Url: http://lambda.jimpryor.net/git/gitweb.cgi?p=lambda.git;a=blobdiff_plain;f=lambda_evaluator.mdwn;h=c0697abd148f771170b18087c9af813f601cb8df;hp=2c6086bf3502cc7f67e452b8c9473d30fcb3c60a;hb=efc414adb5e2372295701927bc1115afedf44ce7;hpb=6f288f5b1aaa1d42e7f98682e74143fc66e1b53c

diff --git a/lambda_evaluator.mdwn b/lambda_evaluator.mdwn
index 2c6086bf..c0697abd 100644
--- a/lambda_evaluator.mdwn
+++ b/lambda_evaluator.mdwn
@@ -22,7 +22,7 @@ Blank lines are fine.
 
 *Abbreviations*: In an earlier version, you couldn't use abbreviations. `\x y. y x x` had to be written `(\x (\y ((y x) x)))`. We've upgraded the parser though, so now it should be able to understand any lambda term that you can.
 
-*Constants*:  (NOT YET IMPLEMENTED!) The combinators `S`, `K`, `I`, `C`, `B`, `W`, and `T` are pre-defined to their standard values. Also, integers will automatically be converted to Church numerals. (`0` is `\s z. z`, `1` is `\s z. s z`, and so on.)
+*Constants*: The combinators `S`, `K`, `I`, `C`, `B`, `W`, and `T` are pre-defined to their standard values. Also, integers will automatically be converted to Church numerals. (`0` is `\s z. z`, `1` is `\s z. s z`, and so on.)
 
 
 
@@ -38,6 +38,7 @@ let and = \l r. l r false in
 )
 </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>
@@ -78,15 +79,16 @@ Object.prototype.error = function (message, t) {
     var parse = make_parse();
 
     function go(source) {
-        var string, tree, expr;
+        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 = 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 = '';
-			// string = string + reduce(expr, false, false).to_string();
+			string = '';
+			eta = document.getElementById('ETA').value === "on";
+			string = "("+eta+")"+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);