diff --git a/environments.js b/environments.js
index 51ee39e..d88426e 100644
--- a/environments.js
+++ b/environments.js
@@ -3,13 +3,14 @@
  * with a few built-in (a standard Prelude environment)
  */
 
-// returns the new environment after mutating it
-// values = [(identifier, JLambda expression)]
-
 var errors = require("./errors.js");
 var rep = require("./representation.js");
 
 
+/*
+ * returns the new environment after mutating it
+ * values = [(identifier, JLambda expression)]
+ */
 function extend(env, values) {
   var new_env = {};
   var env_keys = Object.keys(env);
@@ -42,14 +43,7 @@ function lookup(name, env) {
   return value;
 }
 
-var prelude = makeEnv("prelude", [[new rep.Name("e"), new rep.FloatT(Math.E)],
-                                  [new rep.Name("pi"), new rep.FloatT(Math.PI)]]);
-
-var prelude_types = makeEnv("prelude_types",
-                            [[new rep.Name("e"), new rep.TypeOp("Float", [], false)],
-                            [new rep.Name("pi"), new rep.TypeOp("Float", [], false)]]);
-
-module.exports = { prelude : prelude,
-                   prelude_types : prelude_types,
-                   lookup : lookup,
-                   extend : extend };
+module.exports = {
+  lookup : lookup,
+  extend : extend
+};
diff --git a/example.jl b/example.jl
index ada6c55..4599e01 100644
--- a/example.jl
+++ b/example.jl
@@ -1,7 +1,3 @@
-defop 2 Left (a ++ b)
- (a - b)
-
-
 def foo# 3
 
 deftype Foo (A -> B)
@@ -40,9 +36,9 @@ def empty []
 def getFile
   (readFile "./parse.js")
 
-def fileLines
-  (getFile >>=
-   ((mapM_ putStrLn) . lines))
+;;def fileLines
+;;  (getFile >>=
+;;   ((mapM_ putStrLn) . lines))
 
 def (testUnary n)
   ((-n) + n)
@@ -94,3 +90,5 @@ def main
         (unary +
          fileLines +
          (print splitted))
+
+def blah (3 / 4)
diff --git a/closure_conversion.js b/free_vars.js
similarity index 79%
rename from closure_conversion.js
rename to free_vars.js
index ff8e104..602c31d 100644
--- a/closure_conversion.js
+++ b/free_vars.js
@@ -1,4 +1,4 @@
-/* Takes an AST and converts all of the functions into closures.
+/* Takes an AST and converts all of the functions into "closures"
  * A closure is a triple of:
  *  the bound variables in a function or let
  *  the free variables in a function or let
@@ -19,10 +19,8 @@
  */
 
 var rep = require("./representation.js");
-var env = require("./environments.js");
 var errors = require("./errors.js");
 var parser = require("./parse.js");
-var pprint = require("./pprint.js");
 var $ = require("./tools.js");
 var _ = require("underscore");
 
@@ -68,7 +66,7 @@ function fvs(stx) {
   }
 }
 
-function closure_convert(stx) {
+function annotate_fvs(stx) {
   /* Takes a stx object that is either
    * a lambda
    * a let
@@ -106,40 +104,43 @@ function closure_convert(stx) {
   return new rep.Closure(bound_vars, free_variables, stx, []);
 }
 
-function closure_convert_all(stx) {
+/*
+ * This traverse the tree and gathers up all of the free variables of various functions/let bindings
+ */
+function annotate_fvs_all(stx) {
   var closure;
   switch (stx.exprType) {
     case "Let":
-      closure = closure_convert(stx);
-      closure.body.pairs = closure.body.pairs.map(closure_convert_all);
-      closure.body = closure_convert_all(closure.body.body);
+      closure = annotate_fvs(stx);
+      closure.body.pairs = closure.body.pairs.map(annotate_fvs_all);
+      closure.body = annotate_fvs_all(closure.body.body);
       return closure;
     case "Function":
-      closure = closure_convert(stx);
-      closure.body.body = closure_convert_all(closure.body.body);
+      closure = annotate_fvs(stx);
+      closure.body.body = annotate_fvs_all(closure.body.body);
       return closure;
     case "Unary":
-      stx.val = closure_convert_all(stx.val);
+      stx.val = annotate_fvs_all(stx.val);
       return stx;
     case "Application":
-      stx.func = closure_convert_all(stx.func);
-      stx.p = closure_convert_all(stx.p);
+      stx.func = annotate_fvs_all(stx.func);
+      stx.p = annotate_fvs_all(stx.p);
       return stx;
     case "If":
       if (stx.elseexp) {
-        stx.condition = closure_convert_all(stx.condition);
-        stx.thenexp = closure_convert_all(stx.thenexp);
-        stx.elseexp = closure_convert_all(stx.elseexp);
+        stx.condition = annotate_fvs_all(stx.condition);
+        stx.thenexp = annotate_fvs_all(stx.thenexp);
+        stx.elseexp = annotate_fvs_all(stx.elseexp);
         return stx;
       }
       else {
-        stx.condition = closure_convert_all(stx.condition);
-        stx.thenexp = closure_convert_all(stx.thenexp);
+        stx.condition = annotate_fvs_all(stx.condition);
+        stx.thenexp = annotate_fvs_all(stx.thenexp);
         return stx;
       }
       break;
     case "Definition":
-      stx.val = closure_convert_all(stx.val);
+      stx.val = annotate_fvs_all(stx.val);
       return stx;
     default:
       return stx;
@@ -149,11 +150,11 @@ function closure_convert_all(stx) {
 
 function test(src) {
   var ast = parser.parse(src)[0];
-  console.log(JSON.stringify(closure_convert_all(ast), null, 4));
+  console.log(JSON.stringify(annotate_fvs_all(ast), null, 4));
 }
 
 //console.log(test("if something then if a then if b then c else d else rtrrt else some_other_thing"));
 module.export = {
   test : test,
-  closureConvert : closure_convert_all
+  annotate_fvs: annotate_fvs_all
 };
diff --git a/parse.js b/parse.js
index fa25ccb..2c4e23a 100755
--- a/parse.js
+++ b/parse.js
@@ -367,12 +367,17 @@ function parseDataType(tokens, linenum, charnum) {
                              typeName.charnum,
                              "Expected a type operator in data type definition");
   }
-  parameters = parseMany(parse,
+  if (fst(tokens)[0] !== "right_paren") {
+    parameters = parseMany(parse,
                          validName,
                          validFormPar,
                          tokens,
                          charnum,
                          linenum);
+  }
+  else {
+    parameters = [];
+  }
   if (!tokens || (fst(tokens)[0]) !== "right_paren") {
     throw error.JSyntaxError(_.last(parameters).linenum,
                              _.last(parameters).charnum,
@@ -402,7 +407,7 @@ function parseDefType(tokens, linenum, charnum) {
   }
   if (fst(tokens)[0] === "left_paren") {
     /* It's an actual data type definition
-     * i.e. not just a newtype
+     * i.e. not just an alias
      */
     tokens.pop();
     return parseDataType(tokens, linenum, charnum);
@@ -424,7 +429,7 @@ function parseDefType(tokens, linenum, charnum) {
     if (lhs.exprType !== "TypeOperator") {
       throw error.JSyntaxError(lhs.linenum,
                                lhs.charnum,
-                               "left-hand side of type definition was not a type operator");
+                               "left-hand side of type alias was not a type operator");
     }
     rhs = parse(tokens, linenum, charnum);
 
@@ -432,7 +437,7 @@ function parseDefType(tokens, linenum, charnum) {
         rhs.exprType !== "TypeOperator") {
       throw error.JSyntaxError(rhs.linenum,
                                rhs.charnum,
-                               "was expecting an application or type operator on the right-hand side of a type definition");
+                               "was expecting an application or type operator on the right-hand side of a type alias");
     }
     result = addSrcPos(new typ.DefType(lhs, rhs), tokens, rhs.linenum, rhs.charnum);
     return result;
diff --git a/prelude.jl b/prelude.jl
index f94ff6c..1ed259f 100644
--- a/prelude.jl
+++ b/prelude.jl
@@ -4,24 +4,29 @@
 
 
 ;; Type definitions
-deftype String (A300 Char)
+deftype String (Vector Char)
 
-deftype Int Intrinsic
+deftype (Int) Intrinsic
 
-deftype Float Intrinsic
+deftype (Float) Intrinsic
 
-deftype Char Intrinsic
+deftype (Char) Intrinsic
 
-deftype Byte Intrinsic
+deftype (Byte) Intrinsic
 
-deftype Void Intrinsic
+deftype (Void) Intrinsic
 
-deftype IO Intrinsic
+deftype (IO a) Intrinsic
+
+deftype (Vector a) Intrinsic
 
 deftype (List a)
   (Empty |
    (Cons a (List a)))
 
+deftype (Bottom)
+  Undefined
+
 deftype (Maybe a)
   (Nothing |
    (Just a))
@@ -55,3 +60,59 @@ deftype (Either a b)
 ;; I/O functions
 
 (print :: (String -> (IO Void)))
+
+;; Operator definitions
+
+defop 3 Left (a + b)
+  (add a b)
+
+defop 3 Left (a - b)
+  (minus a b)
+
+defop 4 Left (a * b)
+  (mul a b)
+
+defop 4 Left (a / b)
+  (div a b)
+
+defop 5 Right (a ^ b)
+  (pow a b)
+
+defop 3 Left (a ++ b)
+  (listConcat a b)
+
+defop 2 Left (a == b)
+  (eq a b)
+
+defop 2 Left (a > b)
+  (gt a b)
+
+defop 2 Left (a >= b)
+  (gte a b)
+
+defop 2 Left (a < b)
+  (lt a b)
+
+defop 2 Left (a <= b)
+  (lte a b)
+
+defop 2 Left (a && b)
+  (and a b)
+
+defop 2 Left (a || b)
+  (or a b)
+
+defop 1 Left (x : xs)
+  (cons x xs)
+
+defop 1 Left (f $ x)
+  (fapply f x)
+
+defop 1 Left (f . g)
+  (compose f g)
+
+defop 1 Left (a | b)
+  (bitwiseOr a b)
+
+defop 1 Left (a & b)
+  (bitwiseAnd a b)
diff --git a/representation.js b/representation.js
index 3d843d3..39c3543 100644
--- a/representation.js
+++ b/representation.js
@@ -368,31 +368,11 @@ function makeGensym() {
 
 var gensym = makeGensym();
 
-//console.log(isTypeExpr(new Name("T")));
-
-OPInfo = {"+" : [3, "Left"],
-         "-" :  [3, "Left"],
-         "*" :  [4, "Left"],
-         "/" :  [4, "Left"],
-         "^" :  [5, "Right"],
-          "++" : [3, "Left"],
-          "==" : [2, "Left"],
-          ">" :  [2, "Left"],
-          ">=" : [2, "Left"],
-          "<" :  [2, "Left"],
-          "<=" : [2, "Left"],
-          "&&" : [2, "Left"],
-          "||" : [2, "Left"],
+OPInfo = {
           "::" : [2, "Left"],
-          ":" : [1, "Left"],
-          "$" : [1, "Left"],
-          ">>" : [1, "Left"],
-          ">>=" : [1, "Left"],
-          "<$>" : [1, "Left"],
-          "." : [1, "Left"],
           "," : [1, "Left"],
-          "->" : [1, "Right"],
-          "|" : [1, "Left"]};
+          "->" : [1, "Right"]
+         };
 
 module.exports =
    {
diff --git a/tokenize.js b/tokenize.js
index d04c61d..c522acd 100755
--- a/tokenize.js
+++ b/tokenize.js
@@ -1,5 +1,6 @@
 #!  /usr/bin/node
 
+var fs = require("fs");
 var rep = require("./representation.js");
 var $ = require("./tools.js");
 var error = require("./errors.js");
@@ -13,10 +14,7 @@ function isDigit(c) {
   if (isNaN(code)) {
     return false;
   }
-  return (46 < code &&
-          code < 58 ||
-          code < 58 &&
-          code > 46);
+  return (47 < code && code < 58);
 }
 
 function isWhitespace(c) {
@@ -411,8 +409,11 @@ function checkPattern(x, i) {
 }
 
 function tokenizeFull(input) {
+  var preludeSrc = fs.readFileSync("./prelude.jl");
   var matchop;
   var initialPass = tokenizeHelp(input, _.constant(false), true).reverse();
+
+  input = [preludeSrc, input].join("");
   for (var i = 0; i < initialPass.length; i++) {
     if (initialPass.slice(i, i+8).
         map(_.first).
diff --git a/typecheck.js b/typecheck.js
index 7c198c6..e105e94 100644
--- a/typecheck.js
+++ b/typecheck.js
@@ -13,7 +13,7 @@
 var rep = require("./representation.js");
 var env = require("./environments.js");
 
-var TypeOp = rep.TypeOp;
-var TypeVar = rep.TypeVar;
-
-
+/*
+ * Map all bindings with explicit type annotations in the environment
+ */
+function gather_annotations(stx) {