remove useless context manager support in letenv

Technologicat · Technologicat · commit 1faa4e204e91 · 2018-07-25T14:48:33.000+03:00
diff --git a/unpythonic/let.py b/unpythonic/let.py
@@ -227,18 +227,10 @@ def see(x):
         # one-liner
         f2 = lambda lst: (lambda seen: [seen.add(x) or x for x in lst if x not in seen])(seen=set())
 
-        # context manager only
-        def f3(lst):
-            with _env(seen = set()) as myenv:
-                return [myenv.seen.add(x) or x for x in lst if x not in myenv.seen]
-            # myenv still lives due to Python's scoping rules.
-            # This is why we provide a separate let construct
-            # and not just the env class.
-
-        f4 = lambda lst: let(seen=set(),
+        f3 = lambda lst: let(seen=set(),
                              body=lambda e: [e.seen.add(x) or x for x in lst if x not in e.seen])
 
-        f5 = lambda lst: letrec(seen=lambda e: set(),
+        f4 = lambda lst: letrec(seen=lambda e: set(),
                                 see=lambda e: lambda x: begin(e.seen.add(x), x),
                                 body=lambda e: [e.see(x) for x in lst if x not in e.seen])
 
@@ -250,9 +242,8 @@ def f3(lst):
         assert f2(L) == f2(L)
         assert f3(L) == f3(L)
         assert f4(L) == f4(L)
-        assert f5(L) == f5(L)
 
-        assert f(L) == f2(L) == f3(L) == f4(L) == f5(L) == [1, 3, 2, 4]
+        assert f(L) == f2(L) == f3(L) == f4(L) == [1, 3, 2, 4]
 
     uniqify_test()
 
diff --git a/unpythonic/letenv.py b/unpythonic/letenv.py
@@ -3,18 +3,13 @@
 """Environment for let constructs."""
 
 class env:
-    """Bunch with context manager, iterator and subscripting support.
+    """Bunch with iterator and subscripting support.
 
     Iteration and subscripting just expose the underlying dict.
 
     Also works as a bare bunch.
 
     Usage:
-        # with context manager:
-        with env(x = 0) as myenv:
-            print(myenv.x)
-        # DANGER: myenv still exists due to Python's scoping rules.
-
         # bare bunch:
         myenv2 = env(s="hello", orange="fruit", answer=42)
         print(myenv2.s)
@@ -45,16 +40,6 @@ def __getattr__(self, name):
         else:
             raise AttributeError("Name '{:s}' not in environment".format(name))
 
-    # context manager
-    #
-    def __enter__(self):
-        return self
-
-    def __exit__(self, et, ev, tb):
-        # we could nuke our *contents* to make all names in the environment
-        # disappear, but it's simpler and more predictable not to.
-        pass
-
     # iteration
     #
     def __iter__(self):
