All: split types into types, env, printer, core.

- types: low-level mapping to the implementation language.
- core: functions on types that are exposed directly to mal.
- printer: implementation called by pr-str, str, prn, println.
- env: the environment implementation

- Also, unindent all TCO while loops so that the diff of step4 and
  step5 are minimized.

1 files changed, 19 insertions, 21 deletions

diff --git a/python/step2_eval.py b/python/step2_eval.py
index 65972a2..e50d231 100644
--- a/python/step2_eval.py
+++ b/python/step2_eval.py
@@ -1,46 +1,44 @@
 import sys, traceback
 import mal_readline
-from mal_types import (pr_str, sequential_Q, symbol_Q, coll_Q, list_Q,
-                       vector_Q, hash_map_Q, new_symbol, new_function,
-                       new_list, new_vector, new_hash_map, Env, types_ns)
-from reader import (read_str, Blank)
+import mal_types as types
+import reader, printer
 
 # read
 def READ(str):
-    return read_str(str)
+    return reader.read_str(str)
 
 # eval
 def eval_ast(ast, env):
-    if symbol_Q(ast):
+    if types._symbol_Q(ast):
         try:
             return env[ast]
         except:
             raise Exception("'" + ast + "' not found")
-    elif list_Q(ast):
-        return new_list(*map(lambda a: EVAL(a, env), ast))
-    elif vector_Q(ast):
-        return new_vector(*map(lambda a: EVAL(a, env), ast))
-    elif hash_map_Q(ast):
+    elif types._list_Q(ast):
+        return types._list(*map(lambda a: EVAL(a, env), ast))
+    elif types._vector_Q(ast):
+        return types._vector(*map(lambda a: EVAL(a, env), ast))
+    elif types._hash_map_Q(ast):
         keyvals = []
         for k in ast.keys():
             keyvals.append(EVAL(k, env))
             keyvals.append(EVAL(ast[k], env))
-        return new_hash_map(*keyvals)
+        return types._hash_map(*keyvals)
     else:
         return ast  # primitive value, return unchanged
 
 def EVAL(ast, env):
-    #print("EVAL %s" % ast)
-    if not list_Q(ast):
-        return eval_ast(ast, env)
+        #print("EVAL %s" % ast)
+        if not types._list_Q(ast):
+            return eval_ast(ast, env)
 
-    # apply list
-    el = eval_ast(ast, env)
-    f = el[0]
-    return f(*el[1:])
+        # apply list
+        el = eval_ast(ast, env)
+        f = el[0]
+        return f(*el[1:])
 
 def PRINT(exp):
-    return pr_str(exp)
+    return printer._pr_str(exp)
 
 # repl
 repl_env = {} 
@@ -58,6 +56,6 @@ while True:
         if line == None: break
         if line == "": continue
         print(REP(line))
-    except Blank: continue
+    except reader.Blank: continue
     except Exception as e:
         print "".join(traceback.format_exception(*sys.exc_info()))