Add support for display option

docs/source/configuration.rst

@@ -325,13 +325,14 @@ Themes
     A dict where keys are segment names or strings ``{module}.{name}``. Used to 
     specify default values for various keys:
     :ref:`after <config-theme-seg-after>`,
+    :ref:`args <config-themes-seg-args>` (only for function segments),
     :ref:`before <config-theme-seg-before>`,
     :ref:`contents <config-theme-seg-contents>` (only for string segments
     if :ref:`name <config-themes-seg-name>` is defined),
-    :ref:`args <config-themes-seg-args>` (only for function segments). When 
-    using :ref:`local themes <config-ext-local_themes>` values of these keys are 
-    first searched in the segment description, then in ``segment_data`` key of 
-    a local theme, then in ``segment_data`` key of a :ref:`default theme 
+    :ref:`display <config-theme-seg-display`.
+    When using :ref:`local themes <config-ext-local_themes>` values of these 
+    keys are first searched in the segment description, then in ``segment_data`` 
+    key of a local theme, then in ``segment_data`` key of a :ref:`default theme 
     <config-ext-theme>`. For the :ref:`default theme <config-ext-theme>` itself 
     step 2 is obviously avoided.
 
@@ -455,6 +456,12 @@ Themes
         A list of modes where this segment will be included: The segment is 
         *not* included in any modes, *except* for the modes in this list.
 
+    ``display``
+        .. _config-themes-seg-display:
+
+        Boolean. If false disables displaying of the segment.
+        Defaults to ``True``.
+
 Segments
 ========
 

powerline/lint/__init__.py

@@ -668,17 +668,25 @@ shell_colorscheme_spec = (Spec(
 ).context_message('Error while loading shell colorscheme'))
 
 
-generic_keys = set(('exclude_modes', 'include_modes', 'width', 'align', 'name', 'draw_soft_divider', 'draw_hard_divider', 'priority', 'after', 'before'))
+generic_keys = set((
+	'exclude_modes', 'include_modes',
+	'width', 'align',
+	'name',
+	'draw_soft_divider', 'draw_hard_divider',
+	'priority',
+	'after', 'before',
+	'display'
+))
 type_keys = {
-		'function': set(('args', 'module', 'draw_inner_divider')),
-		'string': set(('contents', 'type', 'highlight_group', 'divider_highlight_group')),
-		'filler': set(('type', 'highlight_group', 'divider_highlight_group')),
-		}
+	'function': set(('args', 'module', 'draw_inner_divider')),
+	'string': set(('contents', 'type', 'highlight_group', 'divider_highlight_group')),
+	'filler': set(('type', 'highlight_group', 'divider_highlight_group')),
+}
 required_keys = {
-		'function': set(),
-		'string': set(('contents',)),
-		'filler': set(),
-		}
+	'function': set(),
+	'string': set(('contents',)),
+	'filler': set(),
+}
 function_keys = set(('args', 'module'))
 highlight_keys = set(('highlight_group', 'name'))
 
@@ -1071,6 +1079,7 @@ segments_spec = Spec().optional().list(
 		draw_hard_divider=Spec().type(bool).optional(),
 		draw_soft_divider=Spec().type(bool).optional(),
 		draw_inner_divider=Spec().type(bool).optional(),
+		display=Spec().type(bool).optional(),
 		module=segment_module_spec(),
 		priority=Spec().type(int, float, type(None)).optional(),
 		after=Spec().type(unicode).optional(),
@@ -1101,6 +1110,7 @@ theme_spec = (Spec(
 		Spec(
 			after=Spec().type(unicode).optional(),
 			before=Spec().type(unicode).optional(),
+			display=Spec().type(bool).optional(),
 			args=args_spec().func(lambda *args, **kwargs: check_args(get_all_possible_segments, *args, **kwargs)),
 			contents=Spec().type(unicode).optional(),
 		),

powerline/segment.py

@@ -82,6 +82,9 @@ def gen_segment_getter(pl, ext, common_config, theme_configs, default_module=Non
 			pl.exception('Failed to generate segment from {0!r}: {1}', segment, str(e), prefix='segment_generator')
 			return None
 
+		if not get_key(segment, module, 'display', True):
+			return None
+
 		if segment_type == 'function':
 			highlight_group = [module + '.' + segment['name'], segment['name']]
 		else:

powerline/theme.py

@@ -49,14 +49,15 @@ class Theme(object):
 			for side in ['left', 'right']:
 				for segment in segdict.get(side, []):
 					segment = get_segment(segment, side)
-					if not run_once:
-						if segment['startup']:
-							try:
-								segment['startup'](pl, shutdown_event)
-							except Exception as e:
-								pl.error('Exception during {0} startup: {1}', segment['name'], str(e))
-								continue
-					self.segments[-1][side].append(segment)
+					if segment:
+						if not run_once:
+							if segment['startup']:
+								try:
+									segment['startup'](pl, shutdown_event)
+								except Exception as e:
+									pl.error('Exception during {0} startup: {1}', segment['name'], str(e))
+									continue
+						self.segments[-1][side].append(segment)
 
 	def shutdown(self):
 		for line in self.segments:

tests/test_configuration.py

@@ -171,6 +171,16 @@ class TestLines(TestRender):
 				], width=10)
 
 
+class TestSegments(TestRender):
+	@add_p_arg
+	def test_display(self, p):
+		with replace_item(globals(), 'config', deepcopy(config)):
+			config['themes/test/default']['segments']['left'][0]['display'] = False
+			config['themes/test/default']['segments']['left'][1]['display'] = True
+			config['themes/test/default']['segments']['right'][0]['display'] = False
+			self.assertRenderEqual(p, '{344} g{4-}>>{--}')
+
+
 class TestColorschemesHierarchy(TestRender):
 	@add_p_arg
 	def test_group_redirects(self, p):