Make TodoWidget._markup private again

Introduce proper TodoWidget.mark and TodoWidget.unmark public methods so
we don't have to expose _markup.

topydo/ui/TodoListWidget.py

@@ -16,7 +16,7 @@
 
 import urwid
 
-from topydo.ui.TodoWidget import TodoWidget, markup
+from topydo.ui.TodoWidget import TodoWidget
 from topydo.lib.Utils import translate_key_to_config
 
 
@@ -207,9 +207,10 @@ class TodoListWidget(urwid.LineBox):
         try:
             todo = self.listbox.focus.todo
             todo_id = str(self.view.todolist.number(todo))
-            result = urwid.emit_signal(self, 'toggle_mark', todo_id)
-            attr_spec = {None: markup(todo, result)}
-            self.listbox.focus.widget.set_attr_map(attr_spec)
+            if urwid.emit_signal(self, 'toggle_mark', todo_id):
+                self.listbox.focus.mark()
+            else:
+                self.listbox.focus.unmark()
         except AttributeError:
             # No todo item selected
             pass

topydo/ui/TodoWidget.py

@@ -36,7 +36,7 @@ def _to_urwid_color(p_color):
         return 'h{}'.format(p_color.color)
 
 
-def markup(p_todo, p_focus):
+def _markup(p_todo, p_focus):
     """
     Returns an attribute spec for the colors that correspond to the given todo
     item.
@@ -84,8 +84,8 @@ class TodoWidget(urwid.WidgetWrap):
 
         self.widget = urwid.AttrMap(
             self.columns,
-            markup(p_todo, False),  # no focus
-            markup(p_todo, True)  # focus
+            _markup(p_todo, False),  # no focus
+            _markup(p_todo, True)  # focus
         )
 
         super().__init__(self.widget)
@@ -100,3 +100,9 @@ class TodoWidget(urwid.WidgetWrap):
     def selectable(self):
         # make sure that ListBox will highlight this widget
         return True
+
+    def mark(self):
+        self.widget.set_attr_map({None: _markup(self.todo, True)})
+
+    def unmark(self):
+        self.widget.set_attr_map({None: _markup(self.todo, False)})