[core] Add "merged" pango support

With this commit, it is possible to add pango directives inside every
piece that supports direct output (e.g. defaults/prefix or <module
name>/prefix) and those will be merged - i.e. it is possible to specify
defaults inside "defaults" and override/specify in the particular
modules.

core/output.py

@@ -52,7 +52,6 @@ class block(object):
         text = attr.get('full_text', '')
         if 'full_text' in attr:
             del attr['full_text']
-
         result = '<span '
         for key, value in attr.items():
             result = '{} {}="{}"'.format(result, key, value)

core/theme.py

@@ -2,6 +2,7 @@ import os
 import io
 import json
 import logging
+import copy
 
 import core.event
 import util.algorithm
@@ -15,6 +16,17 @@ PATHS=[
     os.path.expanduser('~/.config/bumblebee-status/themes'),
 ]
 
+def merge_replace(value, new_value, key):
+    if not isinstance(value, dict):
+        return new_value
+    if isinstance(new_value, dict):
+        util.algorithm.merge(value, new_value)
+        return value
+    # right now, merging needs explicit pango support :(
+    if 'pango' in value:
+        value['pango']['full_text'] = new_value
+    return value
+
 class Theme(object):
     def __init__(self, name='default', iconset='auto', raw_data=None):
         self.name = name
@@ -106,17 +118,20 @@ class Theme(object):
                 tmp = self.__data[option]
                 if isinstance(tmp, list):
                     tmp = tmp[self.__widget_count % len(tmp)]
-                value = tmp.get(key, value)
+                value = merge_replace(value, tmp.get(key, value), key)
 
-        value = self.__data.get(key, value)
+        if isinstance(value, dict):
+            value = copy.deepcopy(value)
+
+        value = merge_replace(value, self.__data.get(key, value), key)
 
         if widget.module():
-            value = self.__get(None, widget.module().name(), {}).get(key, value)
+            value = merge_replace(value, self.__get(None, widget.module().name(), {}).get(key, value), key)
 
         if not key in widget.state():
             for state in widget.state():
                 theme = self.__get(widget, state, {})
-                value = theme.get(key, value)
+                value = merge_replace(value, theme.get(key, value), key)
 
         if not type(value) in (list, dict):
             value = self.__keywords.get(value, value)