Add a hook for yaml files.

pre_commit_hooks/check_yaml.py

@@ -0,0 +1,26 @@
+
+import argparse
+import sys
+import yaml
+
+from pre_commit_hooks.util import entry
+
+
+@entry
+def check_yaml(argv):
+    parser = argparse.ArgumentParser()
+    parser.add_argument('filenames', nargs='+', help='Filenames to check.')
+    args = parser.parse_args(argv)
+
+    retval = 0
+    for filename in args.filenames:
+        try:
+            yaml.load(open(filename))
+        except yaml.YAMLError as e:
+            print e
+            retval = 1
+    return retval
+
+
+if __name__ == '__main__':
+    sys.exit(check_yaml())