add %config magic for configuring IPython

IPython/core/interactiveshell.py

@@ -379,6 +379,7 b' class InteractiveShell(SingletonConfigurable, Magic):'
         # This is where traits with a config_key argument are updated
         # from the values on config.
         super(InteractiveShell, self).__init__(config=config)
+        self.configurables = [self]
 
         # These are relatively independent and stateless
         self.init_ipython_dir(ipython_dir)
@@ -602,9 +603,11 b' class InteractiveShell(SingletonConfigurable, Magic):'
 
     def init_display_formatter(self):
         self.display_formatter = DisplayFormatter(config=self.config)
+        self.configurables.append(self.display_formatter)
 
     def init_display_pub(self):
         self.display_pub = self.display_pub_class(config=self.config)
+        self.configurables.append(self.display_pub)
 
     def init_displayhook(self):
         # Initialize displayhook, set in/out prompts and printing system
@@ -620,6 +623,7 b' class InteractiveShell(SingletonConfigurable, Magic):'
             ps_out = self.prompt_out,
             pad_left = self.prompts_pad_left
         )
+        self.configurables.append(self.displayhook)
         # This is a context manager that installs/revmoes the displayhook at
         # the appropriate time.
         self.display_trap = DisplayTrap(hook=self.displayhook)
@@ -1435,6 +1439,7 b' class InteractiveShell(SingletonConfigurable, Magic):'
     def init_history(self):
         """Sets up the command history, and starts regular autosaves."""
         self.history_manager = HistoryManager(shell=self, config=self.config)
+        self.configurables.append(self.history_manager)
 
     #-------------------------------------------------------------------------
     # Things related to exception handling and tracebacks (not debugging)
@@ -1856,6 +1861,7 b' class InteractiveShell(SingletonConfigurable, Magic):'
                                      use_readline=self.has_readline,
                                      config=self.config,
                                      )
+        self.configurables.append(self.Completer)
 
         # Add custom completers to the basic ones built into IPCompleter
         sdisp = self.strdispatchers.get('complete_command', StrDispatch())
@@ -2112,6 +2118,7 b' class InteractiveShell(SingletonConfigurable, Magic):'
 
     def init_alias(self):
         self.alias_manager = AliasManager(shell=self, config=self.config)
+        self.configurables.append(self.alias_manager)
         self.ns_table['alias'] = self.alias_manager.alias_table,
 
     #-------------------------------------------------------------------------
@@ -2120,9 +2127,12 b' class InteractiveShell(SingletonConfigurable, Magic):'
 
     def init_extension_manager(self):
         self.extension_manager = ExtensionManager(shell=self, config=self.config)
+        self.configurables.append(self.extension_manager)
 
     def init_plugin_manager(self):
         self.plugin_manager = PluginManager(config=self.config)
+        self.configurables.append(self.plugin_manager)
+        
 
     #-------------------------------------------------------------------------
     # Things related to payloads
@@ -2130,6 +2140,7 b' class InteractiveShell(SingletonConfigurable, Magic):'
 
     def init_payload(self):
         self.payload_manager = PayloadManager(config=self.config)
+        self.configurables.append(self.payload_manager)
 
     #-------------------------------------------------------------------------
     # Things related to the prefilter
@@ -2137,6 +2148,7 b' class InteractiveShell(SingletonConfigurable, Magic):'
 
     def init_prefilter(self):
         self.prefilter_manager = PrefilterManager(shell=self, config=self.config)
+        self.configurables.append(self.prefilter_manager)
         # Ultimately this will be refactored in the new interpreter code, but
         # for now, we should expose the main prefilter method (there's legacy
         # code out there that may rely on this).

IPython/core/magic.py

@@ -123,6 +123,8 b' class Magic:'
     auto_status = ['Automagic is OFF, % prefix IS needed for magic functions.',
                    'Automagic is ON, % prefix NOT needed for magic functions.']
 
+
+    configurables = None
     #......................................................................
     # some utility functions
 
@@ -132,6 +134,8 b' class Magic:'
         if profile is None:
             self.magic_prun = self.profile_missing_notice
         self.shell = shell
+        if self.configurables is None:
+            self.configurables = []
 
         # namespace for holding state we may need
         self._magic_state = Bunch()
@@ -3607,4 +3611,92 b' Defaulting color scheme to \'NoColor\'"""'
             with open(new_fname, 'w') as f:
                 current.write(nb, f, new_format)
 
+    def magic_config(self, s):
+        """configure IPython
+        
+        %config Class.trait=value
+        or
+        %config Class
+        
+        This magic exposes most of the IPython config system. Any
+        Configurable class should be able to be configured with the simple
+        line:
+        
+            %config Class.trait=value
+        
+        Where `value` will be resolved in the user's namespace, if it is an
+        expression or variable name.
+        
+        Examples
+        --------
+        
+        To see what classes are availabe for config, pass no arguments:
+        In [1]: %config
+        Available objects for config:
+             TerminalInteractiveShell
+             HistoryManager
+             PrefilterManager
+             AliasManager
+             IPCompleter
+             DisplayFormatter
+             DisplayPublisher
+             DisplayHook
+             ExtensionManager
+             PluginManager
+             PayloadManager
+        
+        # To view what is configurable on a given class, just pass the class name
+        In [2]: %config IPCompleter
+        IPCompleter options
+        -----------------
+        IPCompleter.greedy=<CBool>
+            Current: False
+            Activate greedy completion
+            This will enable completion on elements of lists, results of function calls,
+            etc., but can be unsafe because the code is actually evaluated on TAB.
+        
+        # but the real use is in setting values:
+        In [3]: %config IPCompleter.greedy = True
+        
+        # and these values are read from the user_ns if they are variables:
+        In [4]: feeling_greedy=False
+        
+        In [5]: %config IPCompleter.greedy = feeling_greedy
+        
+        """
+        from IPython.config.loader import Config
+        classnames = [ c.__class__.__name__ for c in self.configurables ]
+        line = s.strip()
+        if not line:
+            # print available configurable names
+            print "Available objects for config:"
+            for name in classnames:
+                print "    ", name
+            return
+        elif line in classnames:
+            # `%config TerminalInteractiveShell` will print trait info for
+            # TerminalInteractiveShell
+            c = self.configurables[classnames.index(line)]
+            cls = c.__class__
+            help = cls.class_get_help(c)
+            # strip leading '--' from cl-args:
+            help = re.sub(r'^\-\-', '', help, flags=re.MULTILINE)
+            print help
+            return
+        elif '=' not in line:
+            raise UsageError("Invalid config statement: %r, should be Class.trait = value" % line)
+            
+        
+        # otherwise, assume we are setting configurables.
+        # leave quotes on args when splitting, because we want
+        # unquoted args to eval in user_ns
+        cfg = Config()
+        exec "cfg."+line in locals(), self.user_ns
+        
+        for configurable in self.configurables:
+            try:
+                configurable.update_config(cfg)
+            except Exception as e:
+                error(e)
+
 # end Magic

IPython/lib/pylabtools.py

@@ -257,6 +257,8 b' def import_pylab(user_ns, backend, import_all=True, shell=None):'
 
         cfg = InlineBackendConfig.instance(config=shell.config)
         cfg.shell = shell
+        if cfg not in shell.configurables:
+            shell.configurables.append(cfg)
 
         if backend == backends['inline']:
             from IPython.zmq.pylab.backend_inline import flush_figures