* Completing initial version of interactive tool support: added interactive

mode detection (plain python, `python -i', and ipython supported),
  and my canned initialization for interactive python environment
  (like MYSELF, ARGV).

interactive_tools.py

@@ -1,4 +1,4 @@
-# $Id: interactive_tools.py,v 1.1 2010-01-22 18:46:27 wirawan Exp $
+# $Id: interactive_tools.py,v 1.2 2011-07-18 15:48:52 wirawan Exp $
 #
 # wpylib.interactive_tools
 # Created: 20091204
@@ -7,12 +7,96 @@
 # Simple and dirty tools for interactive python mode
 #
 
+import atexit
+import inspect
+import os
 import sys
 
-def init_interactive():
+MSGLOG = sys.stderr
+
+
+def get_global_namespace_(global_ns):
+  """Internal routine to get global namespace from another function
+  in this module.
+  BEWARE the limitation! This function is rather fragile and must be
+  called such that the stack order is like this (in descending
+  order):
+
+     * global module statement ...
+     * a function from this module
+     * this function
+  """
+  import pprint
+  if global_ns == None:
+    # Use introspection to fetch the global namespace of the calling
+    # function:
+    from inspect import stack
+    caller_info = stack()[2]  # by default, _two_ level up
+    caller_frame = caller_info[0]  # get the frame record
+    g = caller_frame.f_globals
+  else:
+    g = global_ns
+
+  try:
+    builtin_ns = g['__builtins__']
+  except:
+    builtin_ns = None  # this should not ever happen!
+
+  if False: # for debugging only
+    pprint.pprint(stack())
+    print "caller_info = ",
+    pprint.pprint(caller_info)
+    pprint (sorted(g.keys()))
+    pprint (g['__builtins__'])
+  return (g, builtin_ns)
+
+def detect_interactive(global_ns=None):
+  """Detects if we are in an interactive python session.
+  """
+
+  """The detection scheme is rather complex one because each mode has its
+  own way of flagging that it is ``interactive''.
+
+  See some discussions in:
+    http://stackoverflow.com/questions/1212779/detecting-when-a-python-script-is-being-run-interactively
+
+  These are some known cases:
+  * For ipython, see if "__IPYTHON__" is defined in the user's global
+    namespace.
+  * For "python -i" invocation, sys.flags.interactive will be set to True.
+  * For vanilla "python" invocation with no argument, then sys.ps1
+    variable exists.
+  """
+  (g, b) = get_global_namespace_(global_ns)
+  if "__IPYTHON__" in g or hasattr(b, "__IPYTHON__"):
+    return {
+      'session': 'ipython',
+    }
+  elif sys.flags.interactive:
+    return {
+      'session': 'python -i',
+    }
+  elif hasattr(sys, 'ps1'):
+    return {
+      'session': 'python',
+    }
+  else:
+    return False
+
+
+def init_interactive(use_readline=True, global_ns=None):
+  """Perform standard initialization for my scripts.
+  Some options can be given to tweak the environment.
+
+  Under ipython
+  """
   # ERROR: this still does not work. we need to execute the statements
   # in the global (base) namespace, not in this function's namespace.
 
+  (g, b) = get_global_namespace_(global_ns)
+  int_info = detect_interactive(g)
+
+  if use_readline:
     # Assume interactive python, create a completer if it hasn't been
     # loaded. This is needed for e.g. sciclone, jaguar with no ipython
     # there.
@@ -21,7 +105,7 @@ def init_interactive():
       try:
         import readline
       except ImportError:
-        print "Module readline not available."
+        print >>MSGLOG, "Module readline not available."
       else:
         print "Loading classic readline/rlcompleter."
         import rlcompleter
@@ -34,3 +118,19 @@ def init_interactive():
         # register saving handler
         atexit.register(readline.write_history_file, _histfile)
         del _histfile
+
+
+  # Interestingly, under ipython the sys.argv is only "correct" to extract
+  # the program name at the first loading of the script.
+  # So we must capture that:
+  if int_info['session'] == 'ipython' and 'ARGV' not in g:
+    g['ARGV'] = sys.argv
+    try:
+      g['MYSELF'] = os.path.abspath(sys.argv[0])
+    except:
+      pass
+  elif int_info['session'] in ('python', 'python -i'):
+    g.setdefault('MYSELF', sys.argv[0])
+    g.setdefault('ARGV', sys.argv)
+
+#print "_-helo"