Added a class to manage collecting/applying the kwarg dictionaries.

Includes dumping to/loading from json files.
matplotlib · tacaswell · Dec 2, 2013 · Dec 2, 2013 · Dec 2, 2013 · Dec 2, 2013
commit 5963b00b05e4c82bb2e7eec8c020792bd69edcab
diff --git a/lib/matplotlib/rcparam_ng.py b/lib/matplotlib/rcparam_ng.py
@@ -1,15 +1,19 @@
 from __future__ import (absolute_import, division, print_function,
                         unicode_literals)
 import six
-from collections import namedtuple
+from collections import namedtuple, defaultdict
 from copy import copy
+import json
 
 from functools import wraps
 
+import matplotlib
+
 _kw_dict_nm = '_kw_defaults'
 _kw_entry = namedtuple('_kw_entry', ['orig_funtion', 'kw_dict'])
 
 
+
 def set_defaults(cls, key, new_defaults):
     """
     Set a set of default kwargs for the function `key` on
@@ -143,3 +147,114 @@ def reset_defaults(cls, key):
         orig_fun, old_dict = kw_dict.pop(key)
         # reset to the original function
         setattr(cls, key, orig_fun)
+
+def string_to_class(klass):
+    """
+    Turns a string -> a class object
+    """
+    last_level = matplotlib
+    # split the string
+    split_klass = klass.split('.')
+    # strip the matplotlib off the front
+    if split_klass[0] == 'matplotlib':
+        split_klass.pop(0)
+
+    for _k in split_klass:
+        if not hasattr(last_level, _k):
+            raise ValueError("not valid, make msg better")
+        last_level = getattr(last_level, _k)
+    if not isinstance(last_level, type):
+        raise ValueError("not valid, make msg better")
+
+    return last_level
+
+class RcParamsNG(object):
+    """
+    A class for keeping track of default values
+    """
+    def __init__(self, input_dict=None):
+        """
+        Parameters
+        ----------
+        input_dict : dict
+            a dict of dicts.  Top level keys are strings from hte classes
+            inner keys are function names, inner values are kwarg diccts
+
+        """
+        self.core_dict = defaultdict(dict)
+        if input_dict is not None:
+            self.core_dict.update(input_dict)
+
+    def store_default(self, klass, key, new_defaults):
+        """
+        Adds an entry to the core for the given values
+
+        Parameters
+        ----------
+        klass : str
+            string name of class to set defaults for
+
+        key : str
+            function to set the defaults for
+
+        new_defaults : dict
+            dict containing the new defaults (kwarg pairs)
+        """
+        self.core_dict[klass][key] = new_defaults
+
+    def set_defaults(self):
+        """
+        Set the defaults contained in this object.  Use `set_defaults`
+        which removes any existing defaults, leaving only the values
+        in this object in place.
+        """
+        # loop over the core dictionary
+        for klass, kw_pair in six.iteritems(self.core_dict):
+            # turn the string into a class
+            cls = string_to_class(klass)
+            # look over the list of keys and set the defaults
+            for key, default_dict in six.iteritems(kw_pair):
+                set_defaults(cls, key, default_dict)
+
+    def update_defaults(self):
+        """
+        Update to the default values  contained in this object.
+        Use `update_defaults` which leaves non-conflicting defaults
+        in place.
+        """
+        # loop over the core dictionary
+        for klass, kw_pair in six.iteritems(self.core_dict):
+            # turn the string into a class
+            cls = string_to_class(klass)
+            # look over the list of keys and set the defaults
+            for key, default_dict in six.iteritems(kw_pair):
+                update_defaults(cls, key, default_dict)
+
+    def to_json(self, out_file_path):
+        """
+        Dumps default values to json file.  Use `from_json` to
+        recover.
+
+        Parameters
+        ----------
+        out_file_path : str
+            A valid path to save the json file to.  Will overwrite
+            any existing file at path
+        """
+        with open(out_file_path, 'w') as fout:
+            json.dump(self.core_dict, fout, ensure_ascii=False)
+
+    @classmethod
+    def from_json(cls, in_file_path):
+        """
+        Creates a new RcParamsNG object from a json file.  (see
+        `to_json` to dump to json).
+
+        Parameters
+        ----------
+        in_file_path : str
+            Path to a json file to load.
+        """
+        with open(in_file_path, 'r') as fin:
+            in_dict = json.load(fin)
+        return cls(in_dict)