a = !ls, a = %alias now work (captures output or gets ret val for aliases)

IPApi.meta() provides session data storage for extensions.
%alias without args returns a list of tuples instead of printing 
a list.
__IP.meta is now Struct instead of dummy class "Bunch"

IPython/Extensions/ext_rescapture.py

@@ -0,0 +1,66 b''
+# -*- coding: utf-8 -*-
+""" IPython extension: new prefilters for output grabbing 
+
+Provides 
+
+var = %magic blah blah
+
+var = !ls
+
+$Id: genutils.py 1077 2006-01-24 18:15:27Z vivainio $
+
+"""
+
+import IPython.ipapi
+from IPython.genutils import *
+
+ip = IPython.ipapi.get()
+
+import re
+
+def hnd_magic(line,mo):
+    """ Handle a = %mymagic blah blah """
+    #cmd = genutils.make_quoted_expr(mo.group('syscmd'))
+    #mag = 'ipmagic
+    #return "%s = %s"
+    var = mo.group('varname')
+    cmd = mo.group('cmd')
+    expr = make_quoted_expr(cmd)
+    return itpl('$var = ipmagic($expr)')
+
+def hnd_syscmd(line,mo):
+    """ Handle a = !ls """
+    #cmd = genutils.make_quoted_expr(mo.group('syscmd'))
+    #mag = 'ipmagic
+    #return "%s = %s"
+    var = mo.group('varname')
+    cmd = mo.group('cmd')
+    expr = make_quoted_expr(itpl("sc -l =$cmd"))
+    return itpl('$var = ipmagic($expr)')
+
+def install_re_handler(pat, hnd):
+    ip.meta().re_prefilters.append((re.compile(pat), hnd))
+
+def init_handlers():
+
+    ip.meta().re_prefilters = []
+
+    install_re_handler('(?P<varname>[\w\.]+)\s*=\s*%(?P<cmd>.*)',
+                       hnd_magic
+                       )
+    
+    install_re_handler('(?P<varname>[\w\.]+)\s*=\s*!(?P<cmd>.*)',
+                       hnd_syscmd
+                       )
+
+init_handlers()
+
+def regex_prefilter_f(self,line):    
+    for pat, handler in ip.meta().re_prefilters:
+        mo = pat.match(line)
+        if mo:
+            return handler(line,mo)
+    
+    raise IPython.ipapi.TryNext
+
+ip.set_hook('input_prefilter', regex_prefilter_f)     
  No newline at end of file

IPython/Extensions/ipy_system_conf.py

@@ -14,6 +14,5 b' import IPython.ipapi as ip'
 
 import sys
 
-if sys.version_info >= (2,4):
-    # rehashdir extension requires python 2.4
-    import ext_rehashdir
  No newline at end of file
+import ext_rehashdir # %rehashdir magic
+import ext_rescapture # var = !ls and var = %magic

IPython/Magic.py

@@ -1,7 +1,7 b''
 # -*- coding: utf-8 -*-
 """Magic functions for InteractiveShell.
 
-$Id: Magic.py 1077 2006-01-24 18:15:27Z vivainio $"""
+$Id: Magic.py 1089 2006-01-27 19:04:59Z vivainio $"""
 
 #*****************************************************************************
 #       Copyright (C) 2001 Janko Hauser <[e-mail]> and
@@ -2171,14 +2171,15 b' Defaulting color scheme to \'NoColor\'"""'
                 prechar = ''
             else:
                 prechar = self.shell.ESC_MAGIC
-            print 'Alias\t\tSystem Command\n'+'-'*30
+            #print 'Alias\t\tSystem Command\n'+'-'*30
             atab = self.shell.alias_table
             aliases = atab.keys()
             aliases.sort()
+            res = []
             for alias in aliases:
-                print prechar+alias+'\t\t'+atab[alias][1]
-            print '-'*30+'\nTotal number of aliases:',len(aliases)
-            return
+                res.append((alias, atab[alias][1]))                
+            print "Total number of aliases:",len(aliases)
+            return res
         try:
             alias,cmd = par.split(None,1)
         except:
@@ -2443,6 +2444,18 b' Defaulting color scheme to \'NoColor\'"""'
     def magic_sc(self, parameter_s=''):
         """Shell capture - execute a shell command and capture its output.
 
+        DEPRECATED. Suboptimal, retained for backwards compatibility.
+        
+        You should use the form 'var = !command' instead. Example:
+         
+         "%sc -l myfiles = ls ~" should now be written as
+            
+         "myfiles = !ls ~"
+         
+        myfiles.s, myfiles.l and myfiles.n still apply as documented
+        below.
+
+        --
         %sc [options] varname=command
 
         IPython will run the given command using commands.getoutput(), and
@@ -2453,6 +2466,8 b' Defaulting color scheme to \'NoColor\'"""'
         The '=' sign in the syntax is mandatory, and the variable name you
         supply must follow Python's standard conventions for valid names.
 
+        (A special format without variable name exists for internal use)
+
         Options:
 
           -l: list output.  Split the output on newlines into a list before
@@ -2530,9 +2545,6 b' Defaulting color scheme to \'NoColor\'"""'
             _,cmd = parameter_s.split('=',1)
         except ValueError:
             var,cmd = '',''
-        if not var:
-            error('you must specify a variable to assign the command to.')
-            return
         # If all looks ok, proceed
         out,err = self.shell.getoutputerror(cmd)
         if err:
@@ -2543,7 +2555,10 b' Defaulting color scheme to \'NoColor\'"""'
             out = LSString(out)
         if opts.has_key('v'):
             print '%s ==\n%s' % (var,pformat(out))
+        if var:
         self.shell.user_ns.update({var:out})
+        else:
+            return out
 
     def magic_sx(self, parameter_s=''):
         """Shell execute - run a shell command and capture its output.

IPython/ipapi.py

@@ -141,6 +141,15 b' class IPApi:'
         Returns the result of evaluation"""
         return eval(expr,self.user_ns())
 
+    def meta(self):
+        """ Get a session-specific data store
+        
+        Object returned by this method can be used to store
+        data that should persist through the ipython session.
+        """
+        return self.IP.meta
+        
+
 def launch_new_instance(user_ns = None):
     """ Create and start a new ipython instance.
     

IPython/iplib.py

@@ -6,7 +6,7 b' Requires Python 2.3 or newer.'
 
 This file contains all the classes and helper functions specific to IPython.
 
-$Id: iplib.py 1088 2006-01-27 17:16:45Z vivainio $
+$Id: iplib.py 1089 2006-01-27 19:04:59Z vivainio $
 """
 
 #*****************************************************************************
@@ -242,7 +242,7 b' class InteractiveShell(object,Magic):'
         # convenient location for storing additional information and state
         # their extensions may require, without fear of collisions with other
         # ipython names that may develop later.
-        self.meta = Bunch()
+        self.meta = Struct()
 
         # Create the namespace where the user will operate.  user_ns is
         # normally the only one used, and it is passed to the exec calls as
@@ -724,6 +724,8 b' class InteractiveShell(object,Magic):'
         # accepts it.  Probably at least check that the hook takes the number
         # of args it's supposed to.
         dp = getattr(self.hooks, name, None)
+        if name not in IPython.hooks.__all__:
+            print "Warning! Hook '%s' is not one of %s" % (name, IPython.hooks.__all__ )
         if not dp:
             dp = IPython.hooks.CommandChainDispatcher()
         

doc/ChangeLog

@@ -5,6 +5,16 b''
 	NOTE: this DEPRECATES calling ipython with multiple scripts 
 	("ipython a.py b.py c.py")
 	
+	* iplib.py, hooks.py: Added configurable input prefilter,
+	named 'input_prefilter'. See ext_rescapture.py for example
+	usage.
+	
+	* ext_rescapture.py, Magic.py: Better system command output capture
+	through 'var = !ls' (deprecates user-visible %sc). Same notation
+	applies for magics, 'var = %alias' assigns alias list to var.
+	
+	* ipapi.py: added meta() for accessing extension-usable data store.
+
 2006-01-25  Fernando Perez  <[e-mail]>
 
 	* IPython/demo.py (Demo.show): Flush stdout after each block, so