diff --git a/hy/compiler/modfaker.py b/hy/compiler/modfaker.py
index 0fe42c5..61aa552 100644
--- a/hy/compiler/modfaker.py
+++ b/hy/compiler/modfaker.py
@@ -2,43 +2,32 @@ import imp
 from hy.lex.tokenize import tokenize
 
 
-def _add_builtins(mod):
+def _add_native_methods(mod):
     def shim():
-        def _define(symbol, block):
-            globals()[symbol] = block
-
-        def _fn(args, expr):
-            def _(*args, **kwargs):
-                expr(*args, **kwargs)
-            return _
+        def _print(*args, **kwargs):
+            print " ".join([str(x) for x in args])
 
         def _plus(*args):
-            r = 0
-            for arg in args:
-                r += int(arg)
-            return r
+            ret = 0
+            for x in args:
+                ret += int(x)
+            return ret
 
-        def _print(*args):
-            print " ".join(args)
-
-        builtins = {
-            "def": _define,
-            "fn": _fn,
+        natives = {
             "print": _print,
             "+": _plus
         }
 
-        for builtin in builtins:
-            globals()[builtin] = builtins[builtin]
+        for native in natives:
+            globals()[native] = natives[native]
 
     eval(shim.__code__, mod.__dict__)
 
-
 def forge_module(name, fpath, forest):
     mod = imp.new_module(name)
     mod.__file__ = fpath
     mod._hy_forest = forest
-    _add_builtins(mod)
+    _add_native_methods(mod)
 
     def shim():
         for tree in _hy_forest:
diff --git a/hy/lang/builtins.py b/hy/lang/builtins.py
new file mode 100644
index 0000000..310ff65
--- /dev/null
+++ b/hy/lang/builtins.py
@@ -0,0 +1,25 @@
+#
+
+
+def _define(obj):
+    fd = obj.get_invocation()
+    args = fd['args']
+    obj.namespace[args[0]] = args[1]()
+
+
+def _fn(obj):
+    fd = obj.get_invocation()
+    args = fd['args']
+    sig = args[0]
+    meth = args[1]
+
+    def _(*args, **kwargs):
+        # meth validation
+        return meth(*args, **kwargs)
+    return _
+
+
+builtins = {
+    "def": _define,
+    "fn": _fn,
+}
diff --git a/hy/lang/expression.py b/hy/lang/expression.py
index 7f61455..9181429 100644
--- a/hy/lang/expression.py
+++ b/hy/lang/expression.py
@@ -1,4 +1,5 @@
 from hy.lang.hyobj import HYObject
+from hy.lang.builtins import builtins
 
 
 class HYExpression(list, HYObject):
@@ -21,9 +22,16 @@ class HYExpression(list, HYObject):
             "args": args
         }
 
-    def __call__(self, *args, **kwargs):
+    def peek(self):
+        return self.get_invocation()['function']
+
+    def eval(self, *args, **kwargs):
+        fn = self.peek()
+        if fn in builtins:
+            # special-case builtin handling.
+            return builtins[fn](self)
+
         things = []
-        fn = self.get_invocation()['function']
         for child in self.get_children():
             things.append(child())
 
diff --git a/hy/lang/hyobj.py b/hy/lang/hyobj.py
index c7f4ce1..03a8cb8 100644
--- a/hy/lang/hyobj.py
+++ b/hy/lang/hyobj.py
@@ -7,5 +7,8 @@ class HYObject(object):
     def get_children(self):
         return []
 
-    def __call__(self, *args, **kwargs):
+    def eval(self, *args, **kwargs):
         return self
+
+    def __call__(self, *args, **kwargs):
+        return self.eval(*args, **kwargs)
diff --git a/test.hy b/test.hy
deleted file mode 100644
index 2ed227a..0000000
--- a/test.hy
+++ /dev/null
@@ -1,6 +0,0 @@
-; vim: tabstop=2 expandtab shiftwidth=2 softtabstop=2 filetype=lisp
-
-(def square
-  (fn [x] (* x x)))
-
-(print (square 4))
diff --git a/test.py b/test.py
index 7313eac..b290cd6 100644
--- a/test.py
+++ b/test.py
@@ -5,7 +5,7 @@ from hy.lex.tokenize import tokenize
 m = forge_module(
     'test',
     'test.hy',
-    tokenize('(def two (+ 1 1))')
+    tokenize('(def two (fn [] (print (+ 1 1))))')
 )
 
 print m.two