From b70ac127e2c3698ea643b15af7d6bb5783ff3e7e 2012-07-18 16:11:47
From: Bradley M. Froehle <brad.froehle@gmail.com>
Date: 2012-07-18 16:11:47
Subject: [PATCH] embed(): Default to the future compile flags of the calling frame.

---

diff --git a/IPython/core/compilerop.py b/IPython/core/compilerop.py
index 51d5bfa..ee0de31 100644
--- a/IPython/core/compilerop.py
+++ b/IPython/core/compilerop.py
@@ -28,13 +28,26 @@ Authors
 from __future__ import print_function
 
 # Stdlib imports
+import __future__
 from ast import PyCF_ONLY_AST
 import codeop
+import functools
 import hashlib
 import linecache
+import operator
 import time
 
 #-----------------------------------------------------------------------------
+# Constants
+#-----------------------------------------------------------------------------
+
+# Roughtly equal to PyCF_MASK | PyCF_MASK_OBSOLETE as defined in pythonrun.h,
+# this is used as a bitmask to extract future-related code flags.
+PyCF_MASK = functools.reduce(operator.or_,
+                             (getattr(__future__, fname).compiler_flag
+                              for fname in __future__.all_feature_names))
+
+#-----------------------------------------------------------------------------
 # Local utilities
 #-----------------------------------------------------------------------------
 
diff --git a/IPython/frontend/terminal/embed.py b/IPython/frontend/terminal/embed.py
index f6506ee..5335b60 100644
--- a/IPython/frontend/terminal/embed.py
+++ b/IPython/frontend/terminal/embed.py
@@ -34,7 +34,7 @@ try:
 except:
     from IPython.utils.nested_context import nested
 
-from IPython.core import ultratb
+from IPython.core import ultratb, compilerop
 from IPython.core.magic import Magics, magics_class, line_magic
 from IPython.frontend.terminal.interactiveshell import TerminalInteractiveShell
 from IPython.frontend.terminal.ipapp import load_default_config
@@ -162,7 +162,7 @@ class InteractiveShellEmbed(TerminalInteractiveShell):
             print self.exit_msg
 
     def mainloop(self, local_ns=None, module=None, stack_depth=0,
-                 display_banner=None, global_ns=None):
+                 display_banner=None, global_ns=None, compile_flags=None):
         """Embeds IPython into a running python program.
 
         Input:
@@ -180,6 +180,11 @@ class InteractiveShellEmbed(TerminalInteractiveShell):
           the namespace from the intended level in the stack.  By default (0)
           it will get its locals and globals from the immediate caller.
 
+          - compile_flags: A bit field identifying the __future__ features
+          that are enabled, as passed to the builtin `compile` function. If
+          given as None, they are automatically taken from the scope where the
+          shell was called.
+
         Warning: it's possible to use this in a program which is being run by
         IPython itself (via %run), but some funny things will happen (a few
         globals get overwritten). In the future this will be cleaned up, as
@@ -202,11 +207,15 @@ class InteractiveShellEmbed(TerminalInteractiveShell):
             if module is None:
                 global_ns = call_frame.f_globals
                 module = sys.modules[global_ns['__name__']]
+            if compile_flags is None:
+                compile_flags = (call_frame.f_code.co_flags &
+                                 compilerop.PyCF_MASK)
         
         # Save original namespace and module so we can restore them after 
         # embedding; otherwise the shell doesn't shut down correctly.
         orig_user_module = self.user_module
         orig_user_ns = self.user_ns
+        orig_compile_flags = self.compile.flags
         
         # Update namespaces and fire up interpreter
         
@@ -222,6 +231,9 @@ class InteractiveShellEmbed(TerminalInteractiveShell):
             self.user_ns = local_ns
             self.init_user_ns()
 
+        # Compiler flags
+        self.compile.flags = compile_flags
+
         # Patch for global embedding to make sure that things don't overwrite
         # user globals accidentally. Thanks to Richard <rxe@renre-europe.com>
         # FIXME. Test this a bit more carefully (the if.. is new)
@@ -247,6 +259,7 @@ class InteractiveShellEmbed(TerminalInteractiveShell):
         # Restore original namespace so shell can shut down when we exit.
         self.user_module = orig_user_module
         self.user_ns = orig_user_ns
+        self.compile.flags = orig_compile_flags
 
 _embedded_shell = None