Create empty segment for single-side statuslines

powerline/colorscheme.py

@@ -2,14 +2,14 @@
 
 
 class Colorscheme(object):
-	default_mode_key = '__default__'
+	DEFAULT_MODE_KEY = '__default__'
 
 	def __init__(self, colorscheme):
 		'''Initialize a colorscheme.
 		'''
 		self.colors = {}
 		self.modes_groups = {
-			self.default_mode_key: {}
+			self.DEFAULT_MODE_KEY: {}
 		}
 
 		# Create a dict of color tuples with both a cterm and hex value
@@ -23,7 +23,7 @@ class Colorscheme(object):
 		for group_name, group_props in colorscheme['groups'].items():
 			group_attr_flag = self._get_attr_flag(group_props.get('attr', []))
 
-			self.modes_groups[self.default_mode_key][group_name] = {
+			self.modes_groups[self.DEFAULT_MODE_KEY][group_name] = {
 				'fg': self.colors[group_props['fg']],
 				'bg': self.colors[group_props['bg']],
 				'attr': group_attr_flag,
@@ -73,7 +73,7 @@ class Colorscheme(object):
 		the default mode is returned.
 		'''
 		if not mode or mode not in self.modes_groups:
-			mode = self.default_mode_key
+			mode = self.DEFAULT_MODE_KEY
 
 		try:
 			return self.modes_groups[mode][group]

powerline/renderer.py

@@ -63,11 +63,11 @@ class Renderer(object):
 		'''
 		rendered_highlighted = u''
 		segments_len = len(self.segments)
-		mode = mode if mode in self.segments[0]['highlight'] else Colorscheme.default_mode_key
+		mode = mode if mode in self.segments[0]['highlight'] else Colorscheme.DEFAULT_MODE_KEY
 
 		for index, segment in enumerate(self.segments):
-			prev_segment = self.segments[index - 1] if index > 0 else None
-			next_segment = self.segments[index + 1] if index < segments_len - 1 else None
+			prev_segment = self.segments[index - 1] if index > 0 else self.theme.EMPTY_SEGMENT
+			next_segment = self.segments[index + 1] if index < segments_len - 1 else self.theme.EMPTY_SEGMENT
 			compare_segment = next_segment if segment['side'] == 'left' else prev_segment
 
 			segment['rendered_raw'] = u''

powerline/theme.py

@@ -9,6 +9,11 @@ class Theme(object):
 		self.dividers = theme_config.get('dividers', common_config['dividers'])
 		self.segments = []
 
+		self.EMPTY_SEGMENT = {
+			'contents': None,
+			'highlight': {self.colorscheme.DEFAULT_MODE_KEY: {'fg': (False, False), 'bg': (False, False), 'attr': 0}}
+		}
+
 		for side in ['left', 'right']:
 			for segment in theme_config['segments'].get(side, []):
 				contents = None