Add hide_all command

Fixes #60.

README.org

@@ -170,6 +170,9 @@ The most useful application of this functionality is probably when opening video
 mime ^video, has mpv, X, flag f = tdrop -a auto_hide && mpv -- "$@" && tdrop -a auto_show
 #+END_EXAMPLE
 
+** Other Commands
+If =hide_all= is given instead of a program name, tdrop will hide all visible dropdowns.
+
 * Tested With
 ** Terminals
 These terminals have been tested with tdrop and support the =-s= and =-a= flags unless otherwise specified:

tdrop

@@ -6,8 +6,10 @@ mkdir -p "$MUTDROP_PATH" -m 700
 
 print_help() {
 	echo "
-usage: tdrop [options] <program> or 'current' or
-                       one of 'auto_show'/'auto_hide'/'toggle_auto_hide'
+usage: tdrop [options] <program> [program options ...]
+                       or 'current'
+                       or one of 'auto_show'/'auto_hide'/'toggle_auto_hide'
+                       or 'hide_all'
 options:
 	-h height	specify a height for a newly created term (default: 45%)
 	-w width	specify a width for a newly created term (default: 100%)
@@ -177,7 +179,7 @@ if [[ -z $program_flags ]]; then
 fi
 
 # check that the program is not a path and does not contain flags
-if [[ ! $program =~ ^(current|auto_hide|auto_show|toggle_auto_hide)$ ]] && \
+if [[ ! $program =~ ^(current|auto_hide|auto_show|toggle_auto_hide|hide_all)$ ]] && \
 	   ! type "$program" &> /dev/null; then
 	echo >&2 "The program should be in PATH and not contain flags." | \
 		tee -a "$MUTDROP_PATH"/log
@@ -844,6 +846,19 @@ auto_show() {
 	fi
 }
 
+# * Hide All
+hide_all() {
+	shopt -s nullglob dotglob
+	local dropdowns
+	dropdowns=("$MUTDROP_PATH"/*)
+	for dropdown in "${dropdowns[@]}"; do
+		# cat to silence errors
+		wid=$(cat "$dropdown" 2> /dev/null)
+		unmap "$wid" 2> /dev/null
+	done
+	shopt -u nullglob dotglob
+}
+
 # * Main
 # ** Setup
 set_wm
@@ -860,6 +875,8 @@ elif [[ $program == auto_hide ]]; then
 	auto_hide
 elif [[ $program == auto_show ]]; then
 	auto_show
+elif [[ $program == hide_all ]]; then
+	hide_all
 else
 	wid_toggle
 fi

tdrop.1

@@ -4,13 +4,16 @@
 .SH NAME
 Tdrop - make dropdown terminals and windows
 .SH SYNOPSIS
-tdrop [\fIOPTIONS\fR] [program name or cmd]
+tdrop [\fIOPTIONS\fR] [program name or cmd] [program options ...]
 .SH DESCRIPTION
 	Tdrop is used for hiding/unhiding programs to acheive quake/dropdown functionality. It can create a dropdown window if one does not already exist or turn the current window into a dropdown on the fly. It provides options to control the intial size and position of dropdowns, for example to leave panels visible or to deal with window borders. When used with a terminal, it provides an option to specify the name of a tmux session to automatically start. It also allows the user to specify arbitrary options/flags to be used when starting programs. It uses window IDs as opposed to classes, so it can be used with multiple windows of the same program.
 
 	It also has the ability to automatically hide and automatically show dropdowns. For example, it can be used to automatically hide a terminal when opening something from it, e.g. an image viewer, video player, etc. Tdrop can         then automatically bring back the terminal whenever the image view, video player, etc. is closed. See the Examples section for more information.
 .SH Commands
-Tdrop expects the name of a program or 'current' (to use the current window) as the last argument to create a dropdown (optionally followed by any flags to that program). Alternatively, it can take one of auto_show, auto_hide, or toggle_auto_hide. Neither functionality is particularly useful called directly from the command line; the former should be bound to a key, and the latter is better used in shell functions/aliases or with a file opener (e.g. in the rifle.conf).
+Tdrop expects the name of a program or 'current' (to use the current window) as the last argument to create a dropdown (optionally followed by any flags to that program). Alternatively, it can take one of auto_show, auto_hide, toggle_auto_hide, or hide_all. If hide_all is given instead of a program name, tdrop will hide all visible dropdowns.
+
+Tdrop's functionality is not particularly useful called directly from the command line. Commands should either be bound to a key, used in shell functions/aliases, or used with a file opener (e.g. in the rifle.conf).
+
 .SH OPTIONS
 .br
 E.g.