Add parsing functions to transform user-config to mpl-config

matplotlib · tacaswell · Dec 2, 2013 · Dec 2, 2013 · Dec 2, 2013 · Dec 2, 2013
commit 8caa77d61c918e4825c3e7a0c6a396a1f081475a
diff --git a/lib/matplotlib/config/config_alias_map.json b/lib/matplotlib/config/config_alias_map.json
@@ -0,0 +1,8 @@
+{
+"lines.linewidth":
+    [
+        "collections.LineCollection:__init__:linewidths",
+        "contour.ContourSet:__init__:linewidths",
+        "lines.Line2D:__init__:linewidth"
+    ]
+}
diff --git a/lib/matplotlib/config/parse_user_config.py b/lib/matplotlib/config/parse_user_config.py
@@ -0,0 +1,66 @@
+import os
+import json
+
+import six
+
+
+LOCAL_DIR = os.path.dirname(os.path.abspath(__file__))
+DEFAULT_ALIAS_MAPPING = os.path.join(LOCAL_DIR, 'config_alias_map.json')
+ALIAS_MAPPING = {}
+
+
+def update_config_from_dict_path(config_dict, dict_path, value):
+    """Set value in a config dictionary using a path string.
+
+    Parameters
+    ----------
+    config_dict : dict
+        Configuration dictionary matching format expected by
+        ``matplotlib.config.mpl_config.MPLConfig``.
+    dict_path : str
+        String with nested dictionary keys separated by a colon.
+        For example, 'a:b:c' maps to the key ``some_dict['a']['b']['c']``.
+    value : object
+        Configuration value.
+    """
+    dict_keys = dict_path.split(':')
+    key_to_set = dict_keys.pop()
+
+    inner_dict = config_dict
+    for key in dict_keys:
+        if key not in inner_dict:
+            inner_dict[key] = {}
+        inner_dict = inner_dict[key]
+    inner_dict[key_to_set] = value
+
+
+def load_config_mapping(filename):
+    """Return dictionary mapping config labels to config paths.
+    """
+    with open(filename) as f:
+        config_mapping = json.load(f)
+    return config_mapping
+
+
+def update_alias_mapping(filename):
+    """Update mappings from user-config aliases to config dict paths. """
+    ALIAS_MAPPING.update(load_config_mapping(filename))
+
+update_alias_mapping(DEFAULT_ALIAS_MAPPING)
+
+
+def user_key_to_dict_paths(key):
+    """Return config-dict paths from user-config alias.
+
+    See also ``update_config_from_dict_path``.
+    """
+    return ALIAS_MAPPING[key]
+
+
+def update_config_dict_from_user_config(config_dict, user_config):
+    """Update internal configuration dict from user-config dict.
+    """
+    for user_key, value in six.iteritems(user_config):
+        dict_paths = user_key_to_dict_paths(user_key)
+        for path in dict_paths:
+            update_config_from_dict_path(config_dict, path, value)
diff --git a/lib/matplotlib/tests/test_config.py b/lib/matplotlib/tests/test_config.py
@@ -0,0 +1,27 @@
+from matplotlib.config.parse_user_config import (
+        update_config_from_dict_path, update_config_dict_from_user_config
+)
+
+
+def test_set_config_dict_path():
+    config_dict = {}
+    update_config_from_dict_path(config_dict, 'a:b:c', 1)
+    assert config_dict['a']['b']['c'] == 1
+
+
+def test_set_config_dict_values_user_config():
+    user_config = {'lines.linewidth': 100}
+    config_dict = {}
+    update_config_dict_from_user_config(config_dict, user_config)
+
+    value = config_dict['collections.LineCollection']['__init__']['linewidths']
+    assert value == 100
+    value = config_dict['contour.ContourSet']['__init__']['linewidths']
+    assert value == 100
+    value = config_dict['lines.Line2D']['__init__']['linewidth']
+    assert value == 100
+
+
+if __name__ == '__main__':
+    from numpy import testing
+    testing.run_module_suite()