diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..918f8dc
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+/.mypy_cache
+/__pycache__
diff --git a/README.md b/README.md
index d6c56d8..819a221 100644
--- a/README.md
+++ b/README.md
@@ -1,23 +1,18 @@
-A switch "statement" for Python. Please don't actually use this.
+A switch "statement" for Python.
 
     x = 5
 
-    switch(x)
-
-    if case(4):
-        assert False
-
-    if case(5):
-        assert True
-        fallthrough()
-
-    if case(lambda x: x > 3):
-        assert True
-
-    if case(6):
-        assert False
-
-    if default():
-        assert False
+    with switch(x) as case:
+        if case(4):
+            assert False
+        if case(5):
+            assert True
+            case.fallthrough()
+        if case(lambda x: x > 3):
+            assert True
+        if case(6):
+            assert False
+        if case.default():
+            assert False
 
 Tests and usage in test.py.
diff --git a/switch.py b/switch.py
index f8e61c6..fe76428 100644
--- a/switch.py
+++ b/switch.py
@@ -1,44 +1,43 @@
-__all__ = ['switch', 'case', 'default', 'fallthrough']
+__all__ = ['switch']
 
-class Switch:
-    def __init__(self, value):
-        self.value    = value
-        self.finished = False
-
-    def case(self, cond):
-        if self.finished:
-            return False
 
-        match = False
+from contextlib import contextmanager
+from typing import (
+    cast,
+    Callable,
+    Generator,
+    Generic,
+    TypeVar,
+    Union,
+)
 
-        if hasattr(cond, '__call__'):
-            if cond(self.value):
-                match = True
-        elif cond == self.value:
-            match = True
 
-        if match:
-            self.finished = True
+T = TypeVar('T')
+GuardT = Callable[[T], bool]
 
-        return match
 
-    def fallthrough(self):
+class Case(Generic[T]):
+    def __init__(self, value: T):
+        self.value = value
         self.finished = False
 
-    def default(self):
-        return not self.finished
+    def __call__(self, cond: Union[T, GuardT]) -> bool:
+        if (self.finished
+                or (hasattr(cond, '__call__')
+                    and not cast(GuardT, cond)(self.value))
+                or cond != self.value):
+            return False
 
-the_switch = None
+        self.finished = True
+        return True
 
-def switch(value):
-    global the_switch
-    the_switch = Switch(value)
+    def fallthrough(self) -> None:
+        self.finished = False
 
-def case(cond):
-    return the_switch.case(cond)
+    def default(self) -> bool:
+        return not self.finished
 
-def fallthrough():
-    the_switch.fallthrough()
 
-def default():
-    the_switch.default()
+@contextmanager
+def switch(value: T) -> Generator[Case[T], None, None]:
+    yield Case(value)
diff --git a/test.py b/test.py
index 506a33b..7749b34 100644
--- a/test.py
+++ b/test.py
@@ -1,30 +1,23 @@
-from switch import *
+from switch import switch
 
 x = 5
 
-switch(x)
-
-if case(4):
-    assert False
-
-if case(5):
-    assert True
-    fallthrough()
-
-if case(5):
-    assert True
-
-if case(5):
-    assert False
-
-if case(6):
-    assert False
-
-
-switch(3)
-
-if case(lambda x: x > 5):
-    assert False
-
-if default():
-    assert True
+with switch(x) as case:
+    if case(4):
+        assert False
+    if case(5):
+        assert True
+        case.fallthrough()
+    if case(5):
+        assert True
+    if case(5):
+        assert False
+    if case(6):
+        assert False
+
+
+with switch(3) as case:
+    if case(lambda x: x > 5):
+        assert False
+    if case.default():
+        assert True