diff --git a/pudb/__init__.py b/pudb/__init__.py
index 6263616..831750d 100644
--- a/pudb/__init__.py
+++ b/pudb/__init__.py
@@ -3,25 +3,47 @@ VERSION = "0.92.6"
 
 
 
-CURRENT_DEBUGGER = [None]
-def set_trace():
-    if CURRENT_DEBUGGER[0] is None:
+CURRENT_DEBUGGER = []
+def _get_debugger():
+    if not CURRENT_DEBUGGER:
         from pudb.debugger import Debugger
         dbg = Debugger()
-        CURRENT_DEBUGGER[0] = dbg
+        CURRENT_DEBUGGER.append(dbg)
+        return dbg
+    else:
+        return CURRENT_DEBUGGER[0]
 
+
+
+
+def run(statement, globals=None, locals=None):
+    _get_debugger().run(statement, globals, locals)
+
+def runeval(expression, globals=None, locals=None):
+    return _get_debugger().runeval(expression, globals, locals)
+
+def runcall(*args, **kwds):
+    return _get_debugger().runcall(*args, **kwds)
+
+def set_trace():
+    import sys
+    _get_debugger().set_trace(sys._getframe().f_back)
+
+
+
+
+def post_mortem(exc_info=None):
+    if exc_info is None:
         import sys
-        dbg.set_trace(sys._getframe().f_back)
+        exc_info = sys.exc_info()
 
+    tb = exc_info[2]
+    while tb.tb_next is not None:
+        tb = tb.tb_next
 
-
-
-def post_mortem(t):
-    p = Debugger()
-    p.reset()
-    while t.tb_next is not None:
-        t = t.tb_next
-    p.interaction(t.tb_frame, t)
+    dbg = _get_debugger()
+    dbg.reset()
+    dbg.interaction(tb.tb_frame, exc_info)
 
 
 
diff --git a/setup.py b/setup.py
index c7b47cd..063aa87 100644
--- a/setup.py
+++ b/setup.py
@@ -70,6 +70,13 @@ setup(name='pudb',
 
           python -m pudb.run my-script.py
 
+      Programming PuDB
+      ----------------
+
+      At the programming language level, PuDB displays the same interface
+      as Python's built-in `pdb module <http://docs.python.org/library/pdb.html>`_.
+      Just replace `pdb` with `pudb`.
+
       License and Dependencies
       ------------------------
 
diff --git a/test/test-api.py b/test/test-api.py
new file mode 100644
index 0000000..472a94e
--- /dev/null
+++ b/test/test-api.py
@@ -0,0 +1,5 @@
+def f():
+    fail
+
+from pudb import runcall
+runcall(f)
diff --git a/test/test-postmortem.py b/test/test-postmortem.py
new file mode 100644
index 0000000..a878047
--- /dev/null
+++ b/test/test-postmortem.py
@@ -0,0 +1,8 @@
+def f():
+    fail
+
+try:
+    f()
+except:
+    from pudb import post_mortem
+    post_mortem()