rptmux

#!/usr/bin/env bash
#
# rptmux
#   adds ratpoison keymaps to generate tmux-bound keypresses off Super modkey
#
# desc:
#   - queries running tmux for its keybinds (not needed, see todo)
#   - generates ratpoison binds off super for the unprefixed tmux key
#   - emits the keys by executing 'rpmeta' wrapper
#   - writes the sourceable ratpoison bindings to tmpfile
#   - invokes ratpoison to source the file, which adds the mappings
#
# todo:
#   - processes only 'prefix' keymap from tmux, ignores rest
#   - tmux-2.2: "list-keys and list-commands can be run without starting the
#     tmux server" so use that, i.e. no longer need to run within tmux
#
# note:
#   old way we did this was to actually execute the tmux command; we do
#   not do that anymore because it doesn't know which session to target,
#   so if we have multiple clients attached to different sessions, only
#   the first one will get it, which would require that we look up the
#   terminal -> pid -> client -> session mapping, which is more
#   difficult, so we just emit a keypress instead (much easier) which
#   works with whatever client we are connected with at present moment
#
# scott@smemsh.net
# https://github.com/smemsh/utilx/
# https://spdx.org/licenses/GPL-2.0
#
##############################################################################

# don't expand pathnames in this script, interacts poorly with emit_mapping()
set -f

# maps between tmux charnames and ratpoison/xorg keysym names
#
declare -A charmap      # keychars -> keysyms
declare -A shiftmap     # as charmap if needs shifting, cf add_maps_puncts()

# ratpoison keymap to enter the bindings into
#
rpmap=top

# name of "ratpoison -c meta" command wrapper
#
rpmetacmd=rpmeta

# string prefix to insert before the bound keysym, eg a
# ratpoison modifier (in this case we prefix 'Super' key)
# todo: specify it, either as arg, env, rcfile
#
rppfx='s-'

# this is the '-T <map>' tmux map that we rebind using the
# Super prefix; any tmux keys in other maps (ie root map) will
# be ignored for the time being
#
tmuxmap='prefix'

# prefix we want to emit (give to rpmeta), this should
# correspond to the tmux prefix in ratpoison parlance (todo:
# query it from tmux instead of having to specify it here)
#
tmuxpfx='C-q'

##############################################################################

#
# tmux -> xorg
# key lookup table
#
# mappings created manually, starting from:
#   xmodmap -pke \
#   | awk '{for (i = 4; i < NF; i++) printf("%s\n", $i)}' \
#   | sort -u \
#   | grep -v -e brokenbar -e plusminus \
#   | grep -E '\<[a-z]{2,}$'
#
add_maps_puncts ()
{
	local arraykey

	charmap[';']=semicolon
	charmap['/']=slash
	charmap['.']=period
	charmap['-']=minus
	charmap['`']=grave
	charmap['=']=equal
	charmap[',']=comma
	charmap['[']=bracketleft
	charmap[']']=bracketright
	charmap["'"]=apostrophe
	charmap['\']=backslash

	# ratpoison acts on "meta" using the following sequence:
	#
	#   (1) reads what keysym name given to "meta"
	#   (2) looks it up with XStringToKeysym()
	#       (example "quotedbl" -> 34 (0x22), see <X11/keysymdef.h>)
	#   (3) gets a platform keycode using XKeysymToKeycode()
	#       (34 -> 48, which can be seem with "xmodmap -pke")
	#   (4) uses this to issue an XSendEvent()
	#
	# however, it isn't smart enough to figure out when it has to
	# send shifted ones, so it always issues the very first
	# (unmodified) keycode.  example:
	#
	#   $ xmodmap -pke | grep quotedbl
	#   keycode  48 = apostrophe quotedbl apostrophe quotedbl
	#
	# so "ratpoison -c 'meta quotedbl'" will inject an apostrophe,
	# not a quotedbl.  to fix this, we have to manually add shift
	# prefixes ourselves for those keys which hang off the shift
	# modifier, and we do this by using a separate dictionary for
	# shifted keys only
	#
	# TODO ideally this would be fixed in ratpoison, because
	# "S-quotedbl" is redundant (it's the same as "S-apostrophe",
	# but "quotedbl" is the same as apostrophe according to
	# ratpoison, it does not have enough awareness)
	#
	shiftmap['&']=ampersand
	shiftmap['^']=asciicircum
	shiftmap['~']=asciitilde
	shiftmap['*']=asterisk
	shiftmap['@']=at
	shiftmap['|']=bar
	shiftmap['{']=braceleft
	shiftmap['}']=braceright
	shiftmap[':']=colon
	shiftmap['$']=dollar
	shiftmap['!']=exclam
	shiftmap['>']=greater
	shiftmap['<']=less
	shiftmap['#']=numbersign
	shiftmap['(']=parenleft
	shiftmap[')']=parenright
	shiftmap['%']=percent
	shiftmap['+']=plus
	shiftmap['?']=question
	shiftmap['"']=quotedbl
	shiftmap['_']=underscore
	shiftmap['Space']=space
}

# map also the rest of the normal keyboard keys
# (just ordinary characters bound to themselves)
#
add_maps_alnums ()
{
	local c

	for c in {0..9} {a..z}; do
		charmap[$c]=$c; done
	
	for c in {A..Z}; do
		shiftmap[$c]=$c; done
}

##############################################################################

emit_mapping ()
{
	local key
	local cmd
	local mapped

	# eat the initial 'bind-key' from tmux list-keys
	shift

	# first arg may be a 'bind-key' argument (like '-r')
	#   which we do not support, only simple binds, no flags
	#   supported
	# UPDATE: in v2.1, tmux adds '-T <keymap>' to every
	#   command, we disregard this from the input by
	#   shifting past it (and only keymap we want to
	#   interact with at all is '-T prefix', the rest we
	#   ignore altogether)
	# TODO: if ever there is "-T map -r" instead of "-r -T
	#   map" this would break... can this happen?)
	#
	if [[ "$1 $2" == "-T $tmuxmap" ]]
	then key=$3
	else return; fi

	# we only handle single-char mappings; in our tmuxrc,
	# only a couple rarely-used binds are chords or
	# symbolics, so those mappings can be skipped for now;
	#
	# TODO: can ratpoison even emit eg control-x ? we should handle
	# arbitrary key sequences if so
	#
	if ((${#key} > 1)) && [[ $key != Space ]]; then
		return; fi

	# new way calls our 'rpmeta' command, which simply emits the key
	# (with added 'S-' prefix if need be; see add_maps_puncts())
	#
	mapped=${charmap[$key]:-${shiftmap[$key]}}
	shiftmapped=${shiftmap[$key]:+'S-'}$mapped
	execmd="$rpmetacmd $tmuxpfx $shiftmapped"
	definecmd="definekey $rpmap $rppfx$mapped exec $execmd"
	echo "$definecmd"
}

emit_mappings ()
{
	local line

	tmux list-keys \
	| while read line; do
		emit_mapping $line; done
}

##############################################################################

# generate the mappings and source them into ratpoison
#
main ()
{
	local tmpfile

	add_maps_puncts
	add_maps_alnums

	tmpfile=`mktemp`
	emit_mappings >| $tmpfile
	rp source $tmpfile
	rm $tmpfile
}

main "$@"