Make the prefilterfrontend take an optional ipython0 instance as the

constructor.

IPython/Shell.py

@@ -634,7 +634,7 b' class MatplotlibMTShell(MatplotlibShellBase,MTInteractiveShell):'
 
     def __init__(self,name,usage=None,rc=Struct(opts=None,args=None),
                  user_ns=None,user_global_ns=None, **kw):
-        user_ns,b2 = self._matplotlib_config(name,user_ns)
+        user_ns,user_global_ns,b2 = self._matplotlib_config(name,user_ns,user_global_ns)
         MTInteractiveShell.__init__(self,name,usage,rc,user_ns,user_global_ns,
                                     banner2=b2,**kw)
 

IPython/frontend/prefilterfrontend.py

@@ -58,14 +58,22 b' class PrefilterFrontEnd(LineFrontEndBase):'
     completion...
     """
     
-    def __init__(self, *args, **kwargs):
+    def __init__(self, ipython0=None, *args, **kwargs):
+        """ Parameters:
+            -----------
+
+            ipython0: an optional ipython0 instance to use for command
+            prefiltering and completion.
+        """
         self.save_output_hooks()
-        # Instanciate an IPython0 interpreter to be able to use the
-        # prefiltering.
-        self.ipython0 = make_IPython()
+        if ipython0 is None:
+            # Instanciate an IPython0 interpreter to be able to use the
+            # prefiltering.
+            ipython0 = make_IPython()
+        self.ipython0 = ipython0
         # Set the pager:
         self.ipython0.set_hook('show_in_pager', 
-                    lambda s, string: self.write("\n"+string))
+                    lambda s, string: self.write("\n" + string))
         self.ipython0.write = self.write
         self._ip = _ip = IPApi(self.ipython0)
         # Make sure the raw system call doesn't get called, as we don't

IPython/frontend/tests/test_prefilterfrontend.py

@@ -16,6 +16,7 b' from IPython.frontend.prefilterfrontend import PrefilterFrontEnd'
 from cStringIO import StringIO
 import string
 import sys
+from IPython.ipapi import get as get_ipython0
 
 class TestPrefilterFrontEnd(PrefilterFrontEnd):
     
@@ -23,8 +24,9 b' class TestPrefilterFrontEnd(PrefilterFrontEnd):'
     output_prompt_template = string.Template('')
 
     def __init__(self):
+        ipython0 = get_ipython0()        
         self.out = StringIO()
-        PrefilterFrontEnd.__init__(self)
+        PrefilterFrontEnd.__init__(self, ipython0=ipython0)
 
     def write(self, string):
        self.out.write(string) 

IPython/ipapi.py

@@ -565,6 +565,19 b' def make_user_ns(user_ns = None):'
     This builds a dict with the minimal information needed to operate as a
     valid IPython user namespace, which you can pass to the various embedding
     classes in ipython.
+
+    This API is currently deprecated. Use ipapi.make_user_namespaces() instead
+    to make both the local and global namespace objects simultaneously.
+
+    :Parameters:
+        user_ns : dict-like, optional
+            The current user namespace. The items in this namespace should be
+            included in the output. If None, an appropriate blank namespace
+            should be created.
+
+    :Returns:
+        A dictionary-like object to be used as the local namespace of the
+        interpreter.
     """
 
     raise NotImplementedError
@@ -575,7 +588,20 b' def make_user_global_ns(ns = None):'
 
     Similar to make_user_ns(), but global namespaces are really only needed in
     embedded applications, where there is a distinction between the user's
-    interactive namespace and the global one where ipython is running."""
+    interactive namespace and the global one where ipython is running.
+
+    This API is currently deprecated. Use ipapi.make_user_namespaces() instead
+    to make both the local and global namespace objects simultaneously.
+
+    :Parameters:
+        ns : dict, optional
+            The current user global namespace. The items in this namespace
+            should be included in the output. If None, an appropriate blank
+            namespace should be created.
+
+    :Returns:
+        A true dict to be used as the global namespace of the interpreter.
+    """
 
     raise NotImplementedError
 
@@ -599,6 +625,20 b' def make_user_namespaces(user_ns = None,user_global_ns = None):'
     namespace synchronize with the globals dict somehow.
 
     Raises TypeError if the provided globals namespace is not a true dict.
+
+    :Parameters:
+        user_ns : dict-like, optional
+            The current user namespace. The items in this namespace should be
+            included in the output. If None, an appropriate blank namespace
+            should be created.
+        user_global_ns : dict, optional
+            The current user global namespace. The items in this namespace
+            should be included in the output. If None, an appropriate blank
+            namespace should be created.
+
+    :Returns:
+        A tuple pair of dictionary-like object to be used as the local namespace
+        of the interpreter and a dict to be used as the global namespace.
     """
 
     if user_ns is None: