Use DollarFormatter to fill in names in ! shell calls.

Closes gh-822

IPython/core/interactiveshell.py

@@ -73,7 +73,8 b' from IPython.utils.pickleshare import PickleShareDB'
 from IPython.utils.process import system, getoutput
 from IPython.utils.strdispatch import StrDispatch
 from IPython.utils.syspathcontext import prepended_to_syspath
-from IPython.utils.text import num_ini_spaces, format_screen, LSString, SList
+from IPython.utils.text import (num_ini_spaces, format_screen, LSString, SList,
+                                DollarFormatter)
 from IPython.utils.traitlets import (Integer, CBool, CaselessStrEnum, Enum,
                                      List, Unicode, Instance, Type)
 from IPython.utils.warn import warn, error, fatal
@@ -2571,7 +2572,7 b' class InteractiveShell(SingletonConfigurable, Magic):'
     # Utilities
     #-------------------------------------------------------------------------
 
-    def var_expand(self,cmd,depth=0):
+    def var_expand(self, cmd, depth=0, formatter=DollarFormatter()):
         """Expand python variables in a string.
 
         The depth argument indicates how many frames above the caller should
@@ -2580,11 +2581,10 b' class InteractiveShell(SingletonConfigurable, Magic):'
         The global namespace for expansion is always the user's interactive
         namespace.
         """
-        res = ItplNS(cmd, self.user_ns,  # globals
-                          # Skip our own frame in searching for locals:
-                          sys._getframe(depth+1).f_locals # locals
-                          )
-        return py3compat.str_to_unicode(str(res), res.codec)
+        ns = self.user_ns.copy()
+        ns.update(sys._getframe(depth+1).f_locals)
+        ns.pop('self', None)
+        return formatter.format(cmd, **ns)
 
     def mktempfile(self, data=None, prefix='ipython_edit_'):
         """Make a new tempfile and return its filename.

IPython/utils/tests/test_text.py

@@ -45,7 +45,7 b' def test_columnize_long():'
     nt.assert_equals(out, '\n'.join(items+['']))
 
 def eval_formatter_check(f):
-    ns = dict(n=12, pi=math.pi, stuff='hello there', os=os)
+    ns = dict(n=12, pi=math.pi, stuff='hello there', os=os, u=u"café", b="café")
     s = f.format("{n} {n//4} {stuff.split()[0]}", **ns)
     nt.assert_equals(s, "12 3 hello")
     s = f.format(' '.join(['{n//%i}'%i for i in range(1,8)]), **ns)
@@ -57,6 +57,12 b' def eval_formatter_check(f):'
     s = f.format("{stuff!r}", **ns)
     nt.assert_equals(s, repr(ns['stuff']))
     
+    # Check with unicode:
+    s = f.format("{u}", **ns)
+    nt.assert_equals(s, ns['u'])
+    # This decodes in a platform dependent manner, but it shouldn't error out
+    s = f.format("{b}", **ns)
+        
     nt.assert_raises(NameError, f.format, '{dne}', **ns)
 
 def eval_formatter_slicing_check(f):

IPython/utils/text.py

@@ -25,6 +25,7 b' import textwrap'
 from string import Formatter
 
 from IPython.external.path import path
+from IPython.testing.skipdoctest import skip_doctest_py3
 from IPython.utils import py3compat
 from IPython.utils.io import nlprint
 from IPython.utils.data import flatten
@@ -621,6 +622,7 b' class EvalFormatter(Formatter):'
         v = eval(name, kwargs)
         return v, name
 
+@skip_doctest_py3
 class FullEvalFormatter(Formatter):
     """A String Formatter that allows evaluation of simple expressions.
     
@@ -635,13 +637,13 b' class FullEvalFormatter(Formatter):'
     
     In [1]: f = FullEvalFormatter()
     In [2]: f.format('{n//4}', n=8)
-    Out[2]: '2'
+    Out[2]: u'2'
     
     In [3]: f.format('{list(range(5))[2:4]}')
-    Out[3]: '[2, 3]'
+    Out[3]: u'[2, 3]'
 
     In [4]: f.format('{3*2}')
-    Out[4]: '6'
+    Out[4]: u'6'
     """
     # copied from Formatter._vformat with minor changes to allow eval
     # and replace the format_spec code with slicing
@@ -675,8 +677,9 b' class FullEvalFormatter(Formatter):'
                 # format the object and append to the result
                 result.append(self.format_field(obj, ''))
 
-        return ''.join(result)
+        return u''.join(py3compat.cast_unicode(s) for s in result)
 
+@skip_doctest_py3
 class DollarFormatter(FullEvalFormatter):
     """Formatter allowing Itpl style $foo replacement, for names and attribute
     access only. Standard {foo} replacement also works, and allows full
@@ -686,13 +689,13 b' class DollarFormatter(FullEvalFormatter):'
     --------
     In [1]: f = DollarFormatter()
     In [2]: f.format('{n//4}', n=8)
-    Out[2]: '2'
+    Out[2]: u'2'
     
     In [3]: f.format('23 * 76 is $result', result=23*76)
-    Out[3]: '23 * 76 is 1748'
+    Out[3]: u'23 * 76 is 1748'
     
     In [4]: f.format('$a or {b}', a=1, b=2)
-    Out[4]: '1 or 2'
+    Out[4]: u'1 or 2'
     """
     _dollar_pattern = re.compile("(.*)\$([\w\.]+)")
     def parse(self, fmt_string):
@@ -703,7 +706,7 b' class DollarFormatter(FullEvalFormatter):'
             continue_from = 0
             for m in self._dollar_pattern.finditer(literal_txt):
                 new_txt, new_field = m.group(1,2)
-                yield (new_txt, new_field, "", "s")
+                yield (new_txt, new_field, "", None)
                 continue_from = m.end()
             
             # Re-yield the {foo} style pattern