ENH: Allow unnamed return values in Returns section of doc string

Developers usually only need the type of a return value
followed by a brief description. However, in some cases
providing a name for a return value can make the documentation
clearer. This enhancement changes the format of the Returns
section such that the type is required, and the name is
optional:

    Returns
    -------
    int
        Description of anonymous integer return value.
    x : str
        Description of string return value named `x`.

With this change, if a colon is not present, then the entire
line is interpreted as the return type. In all other cases,
the Returns section is interpreted according to the current
rules.

Consistent with the current format, if a colon is present, then
the text to the left of the colon is interpreted as the name;
and the text to the right of the colon is interpreted as the
type. This makes the proposed change backwards compatible with
existing documentation.

Author: RelentlessIdiot

numpydoc/docscrape.py

@@ -334,7 +334,10 @@ def _str_param_list(self, name):
         if self[name]:
             out += self._str_header(name)
             for param,param_type,desc in self[name]:
-                out += ['%s : %s' % (param, param_type)]
+                if param_type:
+                    out += ['%s : %s' % (param, param_type)]
+                else:
+                    out += [param]
                 out += self._str_indent(desc)
             out += ['']
         return out

numpydoc/docscrape_sphinx.py

@@ -42,16 +42,37 @@ def _str_summary(self):
     def _str_extended_summary(self):
         return self['Extended Summary'] + ['']
 
+    def _str_returns(self):
+        out = []
+        if self['Returns']:
+            out += self._str_field_list('Returns')
+            out += ['']
+            for param, param_type, desc in self['Returns']:
+                if param_type:
+                    out += self._str_indent(['**%s** : %s' % (param.strip(),
+                                                              param_type)])
+                else:
+                    out += self._str_indent([param.strip()])
+                if desc:
+                    out += ['']
+                    out += self._str_indent(desc, 8)
+                out += ['']
+        return out
+
     def _str_param_list(self, name):
         out = []
         if self[name]:
             out += self._str_field_list(name)
             out += ['']
-            for param,param_type,desc in self[name]:
-                out += self._str_indent(['**%s** : %s' % (param.strip(),
-                                                          param_type)])
-                out += ['']
-                out += self._str_indent(desc,8)
+            for param, param_type, desc in self[name]:
+                if param_type:
+                    out += self._str_indent(['**%s** : %s' % (param.strip(),
+                                                              param_type)])
+                else:
+                    out += self._str_indent(['**%s**' % param.strip()])
+                if desc:
+                    out += ['']
+                    out += self._str_indent(desc, 8)
                 out += ['']
         return out
 
@@ -196,8 +217,9 @@ def __str__(self, indent=0, func_role="obj"):
         out += self._str_index() + ['']
         out += self._str_summary()
         out += self._str_extended_summary()
-        for param_list in ('Parameters', 'Returns', 'Other Parameters',
-                           'Raises', 'Warns'):
+        out += self._str_param_list('Parameters')
+        out += self._str_returns()
+        for param_list in ('Other Parameters', 'Raises', 'Warns'):
             out += self._str_param_list(param_list)
         out += self._str_warnings()
         out += self._str_see_also(func_role)

numpydoc/tests/test_docscrape.py

@@ -47,6 +47,9 @@
 
       In other words, each entry ``out[i,j,...,:]`` is an N-dimensional
       value drawn from the distribution.
+  list of str
+      This is not a real return value.  It exists to test
+      anonymous return values.
 
   Other Parameters
   ----------------
@@ -148,13 +151,19 @@ def test_other_parameters():
     assert desc[0].startswith('A parrot off its mortal coil')
 
 def test_returns():
-    assert_equal(len(doc['Returns']), 1)
+    assert_equal(len(doc['Returns']), 2)
     arg, arg_type, desc = doc['Returns'][0]
     assert_equal(arg, 'out')
     assert_equal(arg_type, 'ndarray')
     assert desc[0].startswith('The drawn samples')
     assert desc[-1].endswith('distribution.')
 
+    arg, arg_type, desc = doc['Returns'][1]
+    assert_equal(arg, 'list of str')
+    assert_equal(arg_type, '')
+    assert desc[0].startswith('This is not a real')
+    assert desc[-1].endswith('anonymous return values.')
+
 def test_notes():
     assert doc['Notes'][0].startswith('Instead')
     assert doc['Notes'][-1].endswith('definite.')
@@ -218,6 +227,9 @@ def test_str():
 
     In other words, each entry ``out[i,j,...,:]`` is an N-dimensional
     value drawn from the distribution.
+list of str
+    This is not a real return value.  It exists to test
+    anonymous return values.
 
 Other Parameters
 ----------------
@@ -226,12 +238,12 @@ def test_str():
 
 Raises
 ------
-RuntimeError :
+RuntimeError
     Some error
 
 Warns
 -----
-RuntimeWarning :
+RuntimeWarning
     Some warning
 
 Warnings
@@ -334,6 +346,11 @@ def test_sphinx_str():
         In other words, each entry ``out[i,j,...,:]`` is an N-dimensional
         value drawn from the distribution.
 
+    list of str
+
+        This is not a real return value.  It exists to test
+        anonymous return values.
+
 :Other Parameters:
 
     **spam** : parrot
@@ -342,13 +359,13 @@ def test_sphinx_str():
 
 :Raises:
 
-    **RuntimeError** :
+    **RuntimeError**
 
         Some error
 
 :Warns:
 
-    **RuntimeWarning** :
+    **RuntimeWarning**
 
         Some warning
 
@@ -698,11 +715,11 @@ def test_class_members_doc():
 
     Methods
     -------
-    a :
+    a
 
-    b :
+    b
 
-    c :
+    c
 
     .. index::