Merge pull request #1657 from tkf/editor-wait-opt

Add `wait` optional argument to `hooks.editor`.  As indicated the discussion for #1655 (superseded by this PR), this allows users to define custom magics that can call editors without waiting for a return value.

IPython/core/hooks.py

@@ -42,6 +42,7 @@ def calljed(self,filename, linenum):
 #*****************************************************************************
 
 import os, bisect
+import subprocess
 import sys
 
 from IPython.core.error import TryNext
@@ -54,7 +55,7 @@ def calljed(self,filename, linenum):
            'show_in_pager','pre_prompt_hook',
            'pre_run_code_hook', 'clipboard_get']
 
-def editor(self,filename, linenum=None):
+def editor(self, filename, linenum=None, wait=True):
     """Open the default editor at the given filename and linenumber.
 
     This is IPython's default editor hook, you can use it as an example to
@@ -76,7 +77,9 @@ def editor(self,filename, linenum=None):
         editor = '"%s"' % editor
 
     # Call the actual editor
-    if os.system('%s %s %s' % (editor,linemark,filename)) != 0:
+    proc = subprocess.Popen('%s %s %s' % (editor, linemark, filename),
+                            shell=True)
+    if wait and proc.wait() != 0:
         raise TryNext()
 
 import tempfile