Transformers for assignment from %magic and \!system calls

IPython/core/inputtransformer.py

@@ -173,3 +173,39 b' def leading_indent():'
                 line = (yield line)
 
 leading_indent.look_in_string = True
+
+def _special_assignment(assignment_re, template):
+    line = ''
+    while True:
+        line = (yield line)
+        if not line or line.isspace():
+            continue
+        
+        m = assignment_re.match(line)
+        if not m:
+            continue
+        
+        parts = []
+        while line is not None:
+            parts.append(line.rstrip('\\'))
+            if not line.endswith('\\'):
+                break
+            line = (yield None)
+        
+        # Output
+        whole = assignment_re.match(' '.join(parts))
+        line = template % (whole.group('lhs'), whole.group('cmd'))
+
+@CoroutineInputTransformer
+def assign_from_system():
+    assignment_re = re.compile(r'(?P<lhs>(\s*)([\w\.]+)((\s*,\s*[\w\.]+)*))'
+                               r'\s*=\s*!\s*(?P<cmd>.*)')
+    template = '%s = get_ipython().getoutput(%r)'
+    return _special_assignment(assignment_re, template)
+
+@CoroutineInputTransformer
+def assign_from_magic():
+    assignment_re = re.compile(r'(?P<lhs>(\s*)([\w\.]+)((\s*,\s*[\w\.]+)*))'
+                               r'\s*=\s*%\s*(?P<cmd>.*)')
+    template = '%s = get_ipython().magic(%r)'
+    return _special_assignment(assignment_re, template)

IPython/core/tests/test_inputtransformer.py

@@ -66,3 +66,19 b' leading_indent_tests = ['
 
 def test_leading_indent():
     tt.check_pairs(wrap_transform(inputtransformer.leading_indent), leading_indent_tests)
+
+assign_magic_tests = [(i, [py3compat.u_format(ol) for ol in o]) for i,o in [
+(['a = %bc de \\', 'fg'], ["a = get_ipython().magic('bc de  fg')"]),
+(['a = %bc de \\', 'fg\\', None], ["a = get_ipython().magic('bc de  fg')"]),
+]]
+
+def test_assign_magic():
+    tt.check_pairs(wrap_transform(inputtransformer.assign_from_magic), assign_magic_tests)
+
+assign_system_tests = [(i, [py3compat.u_format(ol) for ol in o]) for i,o in [
+(['a = !bc de \\', 'fg'], ["a = get_ipython().getoutput('bc de  fg')"]),
+(['a = !bc de \\', 'fg\\', None], ["a = get_ipython().getoutput('bc de  fg')"]),
+]]
+
+def test_assign_system():
+    tt.check_pairs(wrap_transform(inputtransformer.assign_from_system), assign_system_tests)