Don’t mess with hl()+contents

What does hl() mean? It looks like “highlight an empty string”, but is actually
“reset highlight style”. In addition if you are writing “hl()” function for new
renderer you need to care about “contents” variable (in two places!: None for
super() call and (contents or u'') after super() call) though function is
actually doing nothing with it. It is just inconvenient.

powerline/renderer.py

@@ -52,7 +52,7 @@ class Renderer(object):
 
 		if not width:
 			# No width specified, so we don't need to crop or pad anything
-			return self._returned_value(u''.join([segment['_rendered_hl'] for segment in segments]) + self.hl(), segments, output_raw)
+			return self._returned_value(u''.join([segment['_rendered_hl'] for segment in segments]) + self.hlstyle(), segments, output_raw)
 
 		# Create an ordered list of segments that can be dropped
 		segments_priority = [segment for segment in sorted(segments, key=lambda segment: segment['priority'], reverse=True) if segment['priority'] > 0]
@@ -75,7 +75,7 @@ class Renderer(object):
 					segment['_space_right'] += space_side
 			segments_spacers[0]['_space_right'] += distribute_len_remainder
 
-		rendered_highlighted = u''.join([segment['_rendered_hl'] for segment in self._render_segments(mode, theme, segments)]) + self.hl()
+		rendered_highlighted = u''.join([segment['_rendered_hl'] for segment in self._render_segments(mode, theme, segments)]) + self.hlstyle()
 
 		return self._returned_value(rendered_highlighted, segments, output_raw)
 
@@ -177,5 +177,8 @@ class Renderer(object):
 		b = int & 0xff
 		return r, g, b
 
-	def hl(self, contents=None, fg=None, bg=None, attr=None):
+	def hlstyle(fg=None, bg=None, attr=None):
 		raise NotImplementedError
+
+	def hl(self, contents, fg=None, bg=None, attr=None):
+		return self.hlstyle(fg, bg, attr) + (contents or u'')

powerline/renderers/bash_prompt.py

@@ -5,13 +5,13 @@ from powerline.renderers.shell import ShellRenderer
 
 class BashPromptRenderer(ShellRenderer):
 	'''Powerline bash prompt segment renderer.'''
-	def hl(self, contents=None, fg=None, bg=None, attr=None):
+	def hlstyle(self, fg=None, bg=None, attr=None):
 		'''Highlight a segment.
 
 		Returns the default ShellRenderer escape sequence with \[...\] wrapped
 		around it (required in bash prompts).
 		'''
-		return '\[' + super(BashPromptRenderer, self).hl(None, fg, bg, attr) + '\]' + (contents or u'')
+		return '\[' + super(BashPromptRenderer, self).hlstyle(fg, bg, attr) + '\]'
 
 	@staticmethod
 	def escape(string):

powerline/renderers/ipython.py

@@ -5,5 +5,5 @@ from powerline.renderers.shell import ShellRenderer
 
 class IpythonRenderer(ShellRenderer):
 	'''Powerline ipython segment renderer.'''
-	def hl(self, *args, **kwargs):
-		return '\x01' + super(IpythonRenderer, self).hl(*args, **kwargs) + '\x02'
+	def hlstyle(self, *args, **kwargs):
+		return '\x01' + super(IpythonRenderer, self).hlstyle(*args, **kwargs) + '\x02'

powerline/renderers/pango_markup.py

@@ -6,11 +6,13 @@ from powerline.renderer import Renderer
 class PangoMarkupRenderer(Renderer):
 	'''Powerline Pango markup segment renderer.'''
 
-	def hl(self, contents=None, fg=None, bg=None, attr=None):
-		'''Highlight a segment.'''
+	@staticmethod
+	def hlstyle(*args, **kwargs):
 		# We don't need to explicitly reset attributes, so skip those calls
-		if not contents or (not attr and not bg and not fg):
-			return ''
+		return ''
+
+	def hl(self, contents, fg=None, bg=None, attr=None):
+		'''Highlight a segment.'''
 		awesome_attr = []
 		if fg is not None:
 			if fg is not False and fg[1] is not False:

powerline/renderers/shell.py

@@ -5,7 +5,7 @@ from powerline.renderer import Renderer
 
 class ShellRenderer(Renderer):
 	'''Powerline shell segment renderer.'''
-	def hl(self, contents=None, fg=None, bg=None, attr=None):
+	def hlstyle(self, fg=None, bg=None, attr=None):
 		'''Highlight a segment.
 
 		If an argument is None, the argument is ignored. If an argument is
@@ -35,7 +35,7 @@ class ShellRenderer(Renderer):
 			else:
 				if attr & Renderer.ATTR_BOLD:
 					ansi += [1]
-		return '[{0}m'.format(';'.join(str(attr) for attr in ansi)) + (contents or u'')
+		return '[{0}m'.format(';'.join(str(attr) for attr in ansi))
 
 	@staticmethod
 	def escape(string):

powerline/renderers/tmux.py

@@ -5,7 +5,7 @@ from powerline.renderer import Renderer
 
 class TmuxRenderer(Renderer):
 	'''Powerline tmux segment renderer.'''
-	def hl(self, contents=None, fg=None, bg=None, attr=None):
+	def hlstyle(self, fg=None, bg=None, attr=None):
 		'''Highlight a segment.'''
 		# We don't need to explicitly reset attributes, so skip those calls
 		if not attr and not bg and not fg:
@@ -37,4 +37,4 @@ class TmuxRenderer(Renderer):
 					tmux_attr += ['underscore']
 				else:
 					tmux_attr += ['nounderscore']
-		return '#[' + ','.join(tmux_attr) + ']' + (contents or u'')
+		return '#[' + ','.join(tmux_attr) + ']'

powerline/renderers/vim.py

@@ -48,7 +48,7 @@ class VimRenderer(Renderer):
 	def escape(string):
 		return string.replace('%', '%%')
 
-	def hl(self, contents=None, fg=None, bg=None, attr=None):
+	def hlstyle(self, fg=None, bg=None, attr=None):
 		'''Highlight a segment.
 
 		If an argument is None, the argument is ignored. If an argument is
@@ -97,4 +97,4 @@ class VimRenderer(Renderer):
 					guibg='#{0:06x}'.format(hl_group['guibg']) if hl_group['guibg'] != 'NONE' else 'NONE',
 					attr=','.join(hl_group['attr']),
 				))
-		return '%#' + self.hl_groups[(fg, bg, attr)]['name'] + '#' + (contents or u'')
+		return '%#' + self.hl_groups[(fg, bg, attr)]['name'] + '#'

powerline/renderers/zsh_prompt.py

@@ -5,13 +5,13 @@ from powerline.renderers.shell import ShellRenderer
 
 class ZshPromptRenderer(ShellRenderer):
 	'''Powerline zsh prompt segment renderer.'''
-	def hl(self, contents=None, fg=None, bg=None, attr=None):
+	def hlstyle(self, fg=None, bg=None, attr=None):
 		'''Highlight a segment.
 
 		Returns the default ShellRenderer escape sequence with %{...%} wrapped
 		around it (required in zsh prompts).
 		'''
-		return '%{' + super(ZshPromptRenderer, self).hl(None, fg, bg, attr) + '%}' + (contents or u'')
+		return '%{' + super(ZshPromptRenderer, self).hlstyle(None, fg, bg, attr) + '%}'
 
 	@staticmethod
 	def escape(string):