Fix metadata on functions.

- Don't use metadata to store ast, env, params data.
- In Clojure, store metadata on the :meta key of the real metadata.
  This also allows using any datatype as metadata.

1 files changed, 10 insertions, 5 deletions

diff --git a/python/mal_types.py b/python/mal_types.py
index 15e4b6b..74409c9 100644
--- a/python/mal_types.py
+++ b/python/mal_types.py
@@ -38,11 +38,16 @@ def _symbol(str): return Symbol(str)
 def _symbol_Q(exp): return type(exp) == Symbol
 
 # Functions
-def _function(Eval, Env, exp, env, params):
-    def f(*args):
-        return Eval(exp, Env(env, params, args))
-    f.__meta__ = {"exp": exp, "env": env, "params": params}
-    return f
+def _function(Eval, Env, ast, env, params):
+    def gen_fn():
+        def fn(*args):
+            return Eval(ast, Env(env, params, args))
+        fn.__meta__ = None
+        fn.__ast__ = ast
+        fn.__gen_env__ = lambda args: Env(env, params, args)
+        fn.__copy__ = gen_fn
+        return fn
+    return gen_fn()
 def _function_Q(f): return type(f) == type(function_Q)
 
 # lists