Merge pull request #7 from minrk/utils

add traitlets.utils.importstring

traitlets/__init__.py

@@ -1,2 +1,3 @@
 from .traitlets import *
+from .utils.importstring import import_item
 from ._version import version_info, __version__

traitlets/traitlets.py

@@ -54,11 +54,11 @@
 from warnings import warn
 
 from ipython_genutils import py3compat
-from .getargspec import getargspec
-from ipython_genutils.importstring import import_item
 from ipython_genutils.py3compat import iteritems, string_types
 
-from .sentinel import Sentinel
+from .utils.getargspec import getargspec
+from .utils.importstring import import_item
+from .utils.sentinel import Sentinel
 SequenceTypes = (list, tuple, set, frozenset)
 
 #-----------------------------------------------------------------------------

traitlets/utils/importstring.py

@@ -0,0 +1,39 @@
+# encoding: utf-8
+"""
+A simple utility to import something by its string name.
+"""
+
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+
+
+def import_item(name):
+    """Import and return ``bar`` given the string ``foo.bar``.
+
+    Calling ``bar = import_item("foo.bar")`` is the functional equivalent of
+    executing the code ``from foo import bar``.
+
+    Parameters
+    ----------
+    name : string
+      The fully qualified name of the module/package being imported.
+
+    Returns
+    -------
+    mod : module object
+       The module that was imported.
+    """
+
+    parts = name.rsplit('.', 1)
+    if len(parts) == 2:
+        # called with 'foo.bar....'
+        package, obj = parts
+        module = __import__(package, fromlist=[obj])
+        try:
+            pak = getattr(module, obj)
+        except AttributeError:
+            raise ImportError('No module named %s' % obj)
+        return pak
+    else:
+        # called with un-dotted string
+        return __import__(parts[0])