Improve powerline-lemonbar documentation

Changes:

- Usage determination transferred back to argparse (it wraps).
- Added complete description of lemonbar script to wm-widgets.rst.
- --interval and --height got their arguments clarified by metavar: it was not
  clear what units they use.
- --bar-command got its metavar because it is better then default BAR_COMMAND.
- --bar-command short variant is now -C.

docs/source/usage/wm-widgets.rst

@@ -73,6 +73,12 @@ Running the binding in i3-mode will require `i3ipc <https://github.com/acrisci/i
 See the `lemonbar documentation <https://github.com/LemonBoy/bar>`_ for more 
 information and options.
 
+All ``powerline-lemonbar.py`` arguments:
+
+.. automan:: powerline.commands.lemonbar
+   :prog: powerline-lemonbar.py
+   :minimal: true
+
 I3 bar
 ======
 

powerline/bindings/lemonbar/powerline-lemonbar.py

@@ -7,39 +7,14 @@ import re
 import subprocess
 
 from threading import Lock, Timer
-from argparse import ArgumentParser, REMAINDER
 
 from powerline.lemonbar import LemonbarPowerline
 from powerline.lib.shell import run_cmd
+from powerline.commands.lemonbar import get_argparser
 
 
 if __name__ == '__main__':
-	parser = ArgumentParser(
-		description='Powerline BAR bindings.',
-		usage='%(prog)s [-h] [--i3] [--height HEIGHT] [--interval INTERVAL] [--bar-command CMD] -- args'
-	)
-	parser.add_argument(
-		'--i3', action='store_true',
-		help='Subscribe for i3 events.'
-	)
-	parser.add_argument(
-		'--height', default='',
-		help='Bar height.'
-	)
-	parser.add_argument(
-		'--interval', '-i',
-		type=float, default=0.5,
-		help='Refresh interval.'
-	)
-	parser.add_argument(
-		'--bar-command', '-c',
-		default='lemonbar',
-		help='Name of the lemonbar executable to use.'
-	)
-	parser.add_argument(
-		'args', nargs=REMAINDER,
-		help='Extra arguments for lemonbar.'
-	)
+	parser = get_argparser()
 	args = parser.parse_args()
 
 	powerline = LemonbarPowerline()

powerline/commands/lemonbar.py

@@ -0,0 +1,35 @@
+# vim:fileencoding=utf-8:noet
+# WARNING: using unicode_literals causes errors in argparse
+from __future__ import (division, absolute_import, print_function)
+
+import argparse
+
+
+def get_argparser(ArgumentParser=argparse.ArgumentParser):
+	parser = ArgumentParser(
+		description='Powerline BAR bindings.'
+	)
+	parser.add_argument(
+		'--i3', action='store_true',
+		help='Subscribe for i3 events.'
+	)
+	parser.add_argument(
+		'--height', default='',
+		metavar='PIXELS', help='Bar height.'
+	)
+	parser.add_argument(
+		'--interval', '-i',
+		type=float, default=0.5,
+		metavar='SECONDS', help='Refresh interval.'
+	)
+	parser.add_argument(
+		'--bar-command', '-C',
+		default='lemonbar',
+		metavar='CMD', help='Name of the lemonbar executable to use.'
+	)
+	parser.add_argument(
+		'args', nargs=argparse.REMAINDER,
+		help='Extra arguments for lemonbar. Should be preceded with ``--`` '
+		     'argument in order not to be confused with script own arguments.'
+	)
+	return parser

tests/run_bar_tests.sh

@@ -117,7 +117,7 @@ if ! test -e "$LEMONBAR_SCRIPT" ; then
 	:
 else
 	enter_suite "lemonbar"
-	for args in "" "-i0.5" "--interval=0.5" "-- test args" "-c bar-aint-recursive" "--height=10"; do
+	for args in "" "-i0.5" "--interval=0.5" "-- test args" "--bar-command bar-aint-recursive" "--height=10"; do
 		rm -rf "$TEST_ROOT/results"
 		run python "$LEMONBAR_SCRIPT" $args > "$TEST_ROOT/lemonbar.log" 2>&1 &
 		SPID=$!
@@ -158,8 +158,8 @@ else
 			height="${height%% *}"
 		fi
 		command="lemonbar"
-		if test "x${args#-c}" != "x$args" ; then
-			command="${args#-c}"
+		if test "x${args#--bar-command}" != "x$args" ; then
+			command="${args#--bar-command}"
 			command="${command# }"
 			command="${command#=}"
 			command="${command%% *}"