Fix for string tests failed due to bad str_overload (#94)

Fix for string tests failed due to bad str_overload

hpat/str_ext.py

@@ -52,22 +52,37 @@ def unliteral_all(args):
 
 ## use objmode for string methods for now
 
-# string methods that just return another string
-str2str_methods = ('capitalize', 'casefold', 'lower', 'lstrip', 'rstrip',
-    'strip', 'swapcase', 'title', 'upper')
-
-for method in str2str_methods:
-    func_text = "def str_overload(in_str):\n"
-    func_text += "  def _str_impl(in_str):\n"
-    func_text += "    with numba.objmode(out='unicode_type'):\n"
-    func_text += "      out = in_str.{}()\n".format(method)
-    func_text += "    return out\n"
-    func_text += "  return _str_impl\n"
-    loc_vars = {}
-    exec(func_text, {'numba': numba}, loc_vars)
-    str_overload = loc_vars['str_overload']
-    overload_method(types.UnicodeType, method)(str_overload)
-
+# string methods that take no arguments and return a string
+str2str_noargs = ('capitalize', 'casefold', 'lower', 'swapcase', 'title', 'upper')
+
+def str_overload_noargs(method):
+    @overload_method(types.UnicodeType, method)
+    def str_overload(in_str):
+        def _str_impl(in_str):
+            with numba.objmode(out='unicode_type'):                
+                out = getattr(in_str, method)()
+            return out
+
+        return _str_impl
+
+for method in str2str_noargs:
+    str_overload_noargs(method)
+
+# strip string methods that take one argument and return a string 
+str2str_1arg = ('lstrip', 'rstrip', 'strip')
+
+def str_overload_1arg(method):
+    @overload_method(types.UnicodeType, method)
+    def str_overload(in_str, arg1):
+        def _str_impl(in_str, arg1):
+            with numba.objmode(out='unicode_type'):
+                out = getattr(in_str, method)(arg1)
+            return out
+
+        return _str_impl
+
+for method in str2str_1arg:
+    str_overload_1arg(method)
 
 @overload_method(types.UnicodeType, 'replace')
 def str_replace_overload(in_str, old, new, count=-1):

hpat/tests/test_strings.py

@@ -31,11 +31,6 @@ def test_impl():
         hpat_func = hpat.jit(test_impl)
         self.assertEqual(hpat_func(), test_impl())
 
-    @unittest.skip('numba.errors.LoweringError - fix needed\n'
-                   'Failed in hpat mode pipeline'
-                   '(step: nopython mode backend)\n'
-                   'str_overload() takes 1 positional argument '
-                   'but 2 were given\n')
     def test_str2str(self):
         str2str_methods = ['capitalize', 'casefold', 'lower', 'lstrip',
             'rstrip', 'strip', 'swapcase', 'title', 'upper']