herbstpanel: only show urgent tags

While there, do some housekeeping in shell style.

xdg-config-dir/herbstluftwm/herbstpanel.sh

@@ -14,42 +14,29 @@ if [ -f ~/.config/herbstluftwm/theme ]; then
 	. ~/.config/herbstluftwm/theme
 fi
 
-tagstatus() {
+show_urgent_tags() {
 	mon=$1
 	herbstclient tag_status "$mon" | tr "\t" "\n" | {
-		out=
+		s=
 		while IFS= read -r line; do
-			[ -z "$line" ] && continue
+			[ -n "$line" ] || continue
 			tag=${line#[.:+#%!-]}
 
-			rev=
-			color=$hlwm_color8
 			case $line in
-			:*)	color=$hlwm_foreground
-				;;
-			[#-]*)	color=$hlwm_color14
-				;;
-			[%+]*)	color=$hlwm_color6
-				;;
-			!*)	color=$hlwm_color13
-				focused=$(herbstclient attr tags.focus.name)
-				if [ "$tag" = "$focused" ]; then
-					color=$hlwm_color14
-				fi
+			!*)	focused=$(herbstclient attr tags.focus.name)
+				[ "$tag" != "$focused" ] && s=$s"$line "
 				;;
 			esac
-			o=$o"%{O1}%{U$color+u}%{O5}%{U--u}"
 		done
-		printf "%%{c}%s%%{O1}\n" "$o"
+		printf "%%{l}%%{F%s}%s%%{F-}\n" "$hlwm_color9" "$s"
 	}
 }
 
-taglist() {
+tagstatus() {
 	mon=$1
-	tagstatus "$mon"
-	herbstclient -i "tag_changed|tag_flags" \
-	    | while read -r discard; do
-		tagstatus "$mon"
+	show_urgent_tags "$mon"
+	herbstclient -i "tag_flags" | while read -r discard; do
+		show_urgent_tags "$mon"
 	done
 }
 
@@ -63,10 +50,13 @@ while IFS="	" read -r m x y w h; do
 	center=
 	right=
 	{
-		taglist "$m" &
+		tagstatus "$m" &
 		spoon -t &
 	} | while IFS= read line; do
 		case $line in
+		"%{l}"*)
+			left=$line
+			;;
 		"%{c}"*)
 			center=$line
 			;;
@@ -75,9 +65,8 @@ while IFS="	" read -r m x y w h; do
 			;;
 		esac
 		printf "%s%s%s\n" "$left" "$center" "$right"
-	done | lemonbar-xft -g "$w"x"$h"+"$x"+"$y" \
-	    -B "$hlwm_background" -F "$hlwm_foreground" \
-	    -f "$hlwm_face" | sh &
+	done | lemonbar-xft -g "${w}x${h}+${x}+${y}" \
+	    -B "$hlwm_background" -F "$hlwm_foreground" -f "$hlwm_face" &
 done
 herbstclient -w reload >/dev/null
 kill 0