--- a/incoming.py	Sun Oct 08 10:01:43 2017 +0800
+++ b/incoming.py	Sun Oct 08 10:33:32 2017 +0800
@@ -44,26 +44,28 @@
         patterns = (
             # pep8-specific E9xx
             # https://pep8.readthedocs.io/en/latest/intro.html#error-codes
-            (r'^E9\d{2}', 'error'),
-            (r'^[EWFCN]\d{3}', 'warning'),
+            (r'^(E9\d{2})', 'error'),
+            (r'^([EWFCN]\d{3})', 'warning'),
 
             # yamllint
-            (r'^\[error\] .* \(\S+\)$', 'error'),
-            (r'^\[warning\] .* \(\S+\)$', 'warning'),
+            (r'^\[error\] .* \((\S+)\)$', 'error'),
+            (r'^\[warning\] .* \((\S+)\)$', 'warning'),
 
             # luacheck
-            (r'^\(E\d{3}\)', 'error'),
-            (r'^\(W\d{3}\)', 'warning'),
+            (r'^\((E\d{3})\)', 'error'),
+            (r'^\((W\d{3})\)', 'warning'),
 
             # jshint
-            (r'.* \(E\d{3}\)$', 'error'),
-            (r'.* \(W\d{3}\)$', 'warning'),
+            (r'.* \((E\d{3})\)$', 'error'),
+            (r'.* \((W\d{3})\)$', 'warning'),
         )
 
         for regex, cls in patterns:
             m = re.match(regex, rest)
             if m is not None:
                 item['cls'] = cls
+                if m.lastindex is not None:
+                    item['code'] = m.group(m.lastindex)
                 if cls == 'error':
                     errors += 1
                 elif cls == 'warning':

--- a/tests/test_incoming.py	Sun Oct 08 10:01:43 2017 +0800
+++ b/tests/test_incoming.py	Sun Oct 08 10:33:32 2017 +0800
@@ -3,14 +3,15 @@
 
 def test_match_linter_output():
     mlo = match_linter_output
-    usual_keys = ['cls', 'filename', 'line_number', 'link_end', 'link_start']
+    usual_keys = {'cls', 'filename', 'line_number', 'link_end', 'link_start'}
 
     # flake8
     errors, warnings, extra = mlo('hello.py:42:1: W123 clowntown ahoy')
     assert errors == 0
     assert warnings == 1
-    assert sorted(extra.keys()) == usual_keys
+    assert set(extra) == usual_keys | {'code'}
     assert extra['cls'] == 'warning'
+    assert extra['code'] == 'W123'
     assert extra['filename'] == 'hello.py'
     assert extra['line_number'] == 42
     assert extra['link_start'] == 0
@@ -20,8 +21,9 @@
     errors, warnings, extra = mlo('s p a c e.yml:07:01: [error] oops! (uh-oh)')
     assert errors == 1
     assert warnings == 0
-    assert sorted(extra.keys()) == usual_keys
+    assert set(extra) == usual_keys | {'code'}
     assert extra['cls'] == 'error'
+    assert extra['code'] == 'uh-oh'
     assert extra['filename'] == 's p a c e.yml'
     assert extra['line_number'] == 7
     assert extra['link_start'] == 0
@@ -31,8 +33,9 @@
     errors, warnings, extra = mlo('ham.lua:414:90: (E101) ham is stale')
     assert errors == 1
     assert warnings == 0
-    assert sorted(extra.keys()) == usual_keys
+    assert set(extra) == usual_keys | {'code'}
     assert extra['cls'] == 'error'
+    assert extra['code'] == 'E101'
     assert extra['filename'] == 'ham.lua'
     assert extra['line_number'] == 414
     assert extra['link_start'] == 0
@@ -42,8 +45,9 @@
     errors, warnings, extra = mlo('backwards.js:9091:1: not perfect (W201)')
     assert errors == 0
     assert warnings == 1
-    assert sorted(extra.keys()) == usual_keys
+    assert set(extra) == usual_keys | {'code'}
     assert extra['cls'] == 'warning'
+    assert extra['code'] == 'W201'
     assert extra['filename'] == 'backwards.js'
     assert extra['line_number'] == 9091
     assert extra['link_start'] == 0
@@ -53,7 +57,7 @@
     errors, warnings, extra = mlo('requirements.txt:5:1: PIL is obsolete.')
     assert errors == 0
     assert warnings == 1
-    assert sorted(extra.keys()) == usual_keys
+    assert set(extra) == usual_keys
     assert extra['cls'] == 'warning'
     assert extra['filename'] == 'requirements.txt'
     assert extra['line_number'] == 5