Merge pull request #5321 from takluyver/i5305

Improve assignment regex to match more tuple unpacking syntax

IPython/core/inputtransformer.py

@@ -516,9 +516,17 b' def strip_encoding_cookie():'
         while line is not None:
             line = (yield line)
 
+_assign_pat = \
+r'''(?P<lhs>(\s*)
+    ([\w\.]+)                # Initial identifier
+    (\s*,\s*
+        \*?[\w\.]+)*         # Further identifiers for unpacking
+    \s*?,?                   # Trailing comma
+    )
+    \s*=\s*
+'''
 
-assign_system_re = re.compile(r'(?P<lhs>(\s*)([\w\.]+)((\s*,\s*[\w\.]+)*))'
-                              r'\s*=\s*!\s*(?P<cmd>.*)')
+assign_system_re = re.compile(r'{}!\s*(?P<cmd>.*)'.format(_assign_pat), re.VERBOSE)
 assign_system_template = '%s = get_ipython().getoutput(%r)'
 @StatelessInputTransformer.wrap
 def assign_from_system(line):
@@ -529,8 +537,7 b' def assign_from_system(line):'
     
     return assign_system_template % m.group('lhs', 'cmd')
 
-assign_magic_re = re.compile(r'(?P<lhs>(\s*)([\w\.]+)((\s*,\s*[\w\.]+)*))'
-                             r'\s*=\s*%\s*(?P<cmd>.*)')
+assign_magic_re = re.compile(r'{}%\s*(?P<cmd>.*)'.format(_assign_pat), re.VERBOSE)
 assign_magic_template = '%s = get_ipython().magic(%r)'
 @StatelessInputTransformer.wrap
 def assign_from_magic(line):

IPython/core/tests/test_inputtransformer.py

@@ -41,16 +41,29 b' syntax = \\'
        [(i,py3compat.u_format(o)) for i,o in \
        [(u'a =! ls', "a = get_ipython().getoutput({u}'ls')"),
         (u'b = !ls', "b = get_ipython().getoutput({u}'ls')"),
+        (u'c= !ls', "c = get_ipython().getoutput({u}'ls')"),
+        (u'd == !ls', u'd == !ls'), # Invalid syntax, but we leave == alone.
         ('x=1', 'x=1'), # normal input is unmodified
         ('    ','    '),  # blank lines are kept intact
+        # Tuple unpacking
+        (u"a, b = !echo 'a\\nb'", u"a, b = get_ipython().getoutput({u}\"echo 'a\\\\nb'\")"),
+        (u"a,= !echo 'a'", u"a, = get_ipython().getoutput({u}\"echo 'a'\")"),
+        (u"a, *bc = !echo 'a\\nb\\nc'", u"a, *bc = get_ipython().getoutput({u}\"echo 'a\\\\nb\\\\nc'\")"),
+        # Tuple unpacking with regular Python expressions, not our syntax.
+        (u"a, b = range(2)", u"a, b = range(2)"),
+        (u"a, = range(1)", u"a, = range(1)"),
+        (u"a, *bc = range(3)", u"a, *bc = range(3)"),
         ]],
 
        assign_magic =
        [(i,py3compat.u_format(o)) for i,o in \
        [(u'a =% who', "a = get_ipython().magic({u}'who')"),
         (u'b = %who', "b = get_ipython().magic({u}'who')"),
+        (u'c= %ls', "c = get_ipython().magic({u}'ls')"),
+        (u'd == %ls', u'd == %ls'), # Invalid syntax, but we leave == alone.
         ('x=1', 'x=1'), # normal input is unmodified
         ('    ','    '),  # blank lines are kept intact
+        (u"a, b = %foo", u"a, b = get_ipython().magic({u}'foo')"),
         ]],
 
        classic_prompt =