Backport PR #4758 - fixes for Python 3.4.

IPython/utils/tests/test_text.py

@@ -15,6 +15,7 b''
 import os
 import math
 import random
+import sys
 
 import nose.tools as nt
 
@@ -107,7 +108,12 b' def eval_formatter_no_slicing_check(f):'
     s = f.format('{stuff[slice(1,4)]}', **ns)
     nt.assert_equal(s, 'ell')
     
-    nt.assert_raises(SyntaxError, f.format, "{a[:]}")
+    if sys.version_info >= (3, 4):
+        # String formatting has changed in Python 3.4, so this now works.
+        s = f.format("{a[:]}", a=[1, 2])
+        nt.assert_equal(s, "[1, 2]")
+    else:
+        nt.assert_raises(SyntaxError, f.format, "{a[:]}")
 
 def test_eval_formatter():
     f = text.EvalFormatter()

IPython/utils/text.py

@@ -509,6 +509,9 b' class EvalFormatter(Formatter):'
         v = eval(name, kwargs)
         return v, name
 
+#XXX: As of Python 3.4, the format string parsing no longer splits on a colon
+# inside [], so EvalFormatter can handle slicing. Once we only support 3.4 and
+# above, it should be possible to remove FullEvalFormatter.
 
 @skip_doctest_py3
 class FullEvalFormatter(Formatter):