Rules: Add the 'commas' rule

yamllint/conf/default.yml

@@ -6,9 +6,9 @@ rules:
   colons:
     max-spaces-before: 0
     max-spaces-after: 1
-  #comma:
-  #  max-spaces-before: 0
-  #  max-spaces-after: 1
+  commas:
+    max-spaces-before: 0
+    max-spaces-after: 1
   #comment:
   #  min-spaces-after: 1
   #  min-spaces-before: 2

yamllint/rules/__init__.py

@@ -16,6 +16,7 @@
 
 from yamllint.rules import (
     colons,
+    commas,
     document_end,
     document_start,
     empty_lines,
@@ -29,6 +30,7 @@ from yamllint.rules import (
 
 _RULES = {
     colons.ID: colons,
+    commas.ID: commas,
     document_end.ID: document_end,
     document_start.ID: document_start,
     empty_lines.ID: empty_lines,

yamllint/rules/commas.py

@@ -0,0 +1,38 @@
+# -*- coding: utf-8 -*-
+# Copyright (C) 2016 Adrien Vergé
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import yaml
+
+from yamllint.rules.common import max_spaces_after, max_spaces_before
+
+
+ID = 'commas'
+TYPE = 'token'
+CONF = {'max-spaces-before': int,
+        'max-spaces-after': int}
+
+
+def check(conf, token, prev, next):
+    if isinstance(token, yaml.FlowEntryToken):
+        problem = max_spaces_before(conf['max-spaces-before'], token, prev,
+                                    next, 'too many spaces before comma')
+        if problem is not None:
+            yield problem
+
+        problem = max_spaces_after(conf['max-spaces-after'], token, prev, next,
+                                   'too many spaces after comma')
+        if problem is not None:
+            yield problem