Require keyword arguments be passed by name (ros2/rosidl_python#80)

* Require keyword arguments be passed by name

Also fix style by breaking after open parenthesis.

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Update style

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

rosidl_runtime_py/convert.py

@@ -59,8 +59,13 @@ def __represent_ordereddict(dumper, data):
     return yaml.nodes.MappingNode(u'tag:yaml.org,2002:map', items)
 
 
-def message_to_yaml(msg: Any, truncate_length: int = None,
-                    no_arr: bool = False, no_str: bool = False) -> str:
+def message_to_yaml(
+    msg: Any,
+    *,
+    truncate_length: int = None,
+    no_arr: bool = False,
+    no_str: bool = False
+) -> str:
     """
     Convert a ROS message to a YAML string.
 
@@ -85,8 +90,13 @@ def message_to_yaml(msg: Any, truncate_length: int = None,
     )
 
 
-def message_to_csv(msg: Any, truncate_length: int = None,
-                   no_arr: bool = False, no_str: bool = False) -> str:
+def message_to_csv(
+    msg: Any,
+    *,
+    truncate_length: int = None,
+    no_arr: bool = False,
+    no_str: bool = False
+) -> str:
     """
     Convert a ROS message to string of comma-separated values.
 
@@ -123,7 +133,7 @@ def to_string(val, field_type=None):
                         val += '...'
             r = str(val)
         else:
-            r = message_to_csv(val, truncate_length, no_arr, no_str)
+            r = message_to_csv(val, truncate_length=truncate_length, no_arr=no_arr, no_str=no_str)
         return r
     result = ''
 
@@ -141,10 +151,12 @@ def to_string(val, field_type=None):
 # Convert a msg to an OrderedDict. We do this instead of implementing a generic __dict__() method
 # in the msg because we want to preserve order of fields from the .msg file(s).
 def message_to_ordereddict(
-        msg: Any,
-        truncate_length: int = None,
-        no_arr: bool = False,
-        no_str: bool = False) -> OrderedDict:
+    msg: Any,
+    *,
+    truncate_length: int = None,
+    no_arr: bool = False,
+    no_str: bool = False
+) -> OrderedDict:
     """
     Convert a ROS message to an OrderedDict.
 
@@ -163,15 +175,21 @@ def message_to_ordereddict(
         value = getattr(msg, field_name, None)
 
         value = _convert_value(
-            value, field_type,
+            value, field_type=field_type,
             truncate_length=truncate_length, no_arr=no_arr, no_str=no_str)
         # Remove leading underscore from field name
         d[field_name[1:]] = value
     return d
 
 
-def _convert_value(value, field_type=None,
-                   truncate_length=None, no_arr=False, no_str=False):
+def _convert_value(
+    value,
+    *,
+    field_type=None,
+    truncate_length=None,
+    no_arr=False,
+    no_str=False
+):
 
     if isinstance(value, bytes):
         if truncate_length is not None and len(value) > truncate_length:

test/rosidl_runtime_py/test_convert.py

@@ -37,12 +37,12 @@ def test_primitives():
     msgs.extend(message_fixtures.get_msg_strings())
     msgs.extend(message_fixtures.get_msg_unbounded_sequences())
     for m in msgs:
-        message_to_csv(m, 100)
-        message_to_csv(m, None)
-        message_to_ordereddict(m, 100)
-        message_to_ordereddict(m, None)
-        message_to_yaml(m, 100)
-        message_to_yaml(m, None)
+        message_to_csv(m, truncate_length=100)
+        message_to_csv(m, truncate_length=None)
+        message_to_ordereddict(m, truncate_length=100)
+        message_to_ordereddict(m, truncate_length=None)
+        message_to_yaml(m, truncate_length=100)
+        message_to_yaml(m, truncate_length=None)
 
 
 def test_convert_primitives():