Tail Call Optimization with Brushtail

package.json

@@ -25,7 +25,8 @@
     "escodegen": "0.0.22",
     "source-map": "0.1.8",
     "underscore": "1.2.0",
-    "unicode-categories": "0.9.1"
+    "unicode-categories": "0.9.1",
+    "brushtail": "0.0.1"
   },
   "devDependencies": {
     "jison": "0.2.7",

site/index.htm

@@ -99,6 +99,7 @@ <h2>About</h2>
         <li><a href="http://en.wikipedia.org/wiki/Pattern_matching">Pattern matching</a></li>
         <li><a href="http://en.wikipedia.org/wiki/Structural_type_system">Structural typing</a></li>
         <li><a href="http://en.wikipedia.org/wiki/Monad_%28functional_programming%29#do-notation">Monad syntax</a></li>
+        <li><a href="http://en.wikipedia.org/wiki/Tail_call_optimization">Tail call optimization</a></li>
         <li><a href="http://en.wikipedia.org/wiki/Currying">Automatic currying</a></li>
         <li><a href="http://en.wikipedia.org/wiki/Eager_evaluation">Eager evaluation</a></li>
       </ul>

src/compile.js

@@ -7,6 +7,7 @@ var typecheck = require('./typeinference').typecheck,
     lexer = require('./lexer'),
     parser = require('../lib/parser').parser,
     typeparser = require('../lib/typeparser').parser,
+    brushtail = require('brushtail'),
     escodegen = require('escodegen'),
     _ = require('underscore');
 
@@ -909,6 +910,8 @@ var compile = function(source, env, aliases, opts) {
         });
     }
 
+    brushtail.mutateAST(jsAst);
+
     return {
         type: resultType,
         output: escodegen.generate(

test/CompileSpec.js

@@ -108,5 +108,8 @@ describe('compiler', function(){
         it('with.roy with expected output', function() {
             expectExecutionToHaveExpectedOutput('good/with');
         });
+        it('tco.roy with expected output', function() {
+            expectExecutionToHaveExpectedOutput('good/tco');
+        });
     });
 });

test/fixtures/good/tco.out

@@ -0,0 +1 @@
+1000000

test/fixtures/good/tco.roy

@@ -0,0 +1,7 @@
+let count from to =
+  if from >= to then
+    from
+  else
+    count (from + 1) to
+
+console.log (count 0 1000000)