reflex-watch

#!/usr/bin/env bash
dk.watch() {
	require-any reflex dk use: golang
	require-any reflex go install github.com/bashup/reflex@bashup  # Need reflex for this
	require-any tput  # for pager.watch

	# Trap SIGUSR1 to restart the watch with new configuration
	event quote "$@"
	trap "echo Configuration changed: restarting watch; echo; exec dk watch ""$REPLY" SIGUSR1

	export DEVKIT_PAGER=${DEVKIT_PAGER-pager.watch}     # Use the watch pager by default
	event emit "before_watch" || echo "[$?]"            # Run any watch+ commands
	isatty || export DEVKIT_ISATTY=0                    # reflex always runs w/pseudo-tty

	# Run reflex with our current watch configuration, suppressing "killed" msg
	# via background job + wait
	reflex -d none --sequential "$@" -c <(event emit reflex_config) </dev/null & wait $!
}

watch() {
	# Output the command line as part of the reflex config
	parse-watch "on reflex_config __put-watch" "$@"
}

parse-watch() {
	# Parse `[globs...] [options...] command...`, converting globs to regexes
	local re='' RE='' cmd=$1; shift
	while (($#)) && [[ $1 != -* ]]; do
		if [[ $1 == '!'* ]]; then
			glob2re "${1:1}"
			RE+=\|$REPLY
		else
			glob2re "$1"
			re+=\|$REPLY
		fi
		shift
	done
	[[ ! $RE ]] || set -- -R "^(${RE#|})\$" "$@"
	[[ ! $re ]] || set -- -r "^(${re#|})\$" "$@"
	$cmd "$@"
}

watch+ () {
	# Run the specified command at the start of watch, as well as on changes
	watch "$@"
	while (($#)) && [[ $1 != '--' ]]; do shift; done; [[ ${1-} != '--' ]] || shift
	before watch "$@"
}

RELOAD_MATCH=
RELOAD_REJECT=

watch-reload() {
	# Restart watch if given pattern matches
	parse-watch __add_reload "$@"
}

__add_reload() {
	RELOAD_MATCH+=$re
	RELOAD_REJECT+=$RE
	export WATCH_PID=$$
	[[ ! "$re$RE" ]] || on reflex_config __reload-watch
}

__reload-watch() {
	${RELOAD_REJECT:+ set -- -R "${RELOAD_REJECT#|}" "$@"}
	${RELOAD_MATCH:+  set -- -r "${RELOAD_MATCH#|}"  "$@"}
	__put-watch "$@" -- bash -c 'kill -9 $PPID; kill -SIGUSR1 '$WATCH_PID';'
}

UNWATCH_RE=

unwatch() {
	# Globally exclude the given globs from all watch patterns
	for REPLY; do glob2re "$REPLY"; UNWATCH_RE+=${UNWATCH_RE:+|}"^($REPLY)\$"; done
}

unwatch-re() {
	# Globally exclude the given regexes from all watch patterns
	for REPLY; do UNWATCH_RE+=${UNWATCH_RE:+|}"($REPLY)"
	done
}

__put-watch() {
	# Output a reflex with global exclusion(s) added
	reflex-quote ${UNWATCH_RE:+ -R "$UNWATCH_RE"} "$@"
	echo -E "$REPLY"
}

reflex-quote() {
	# Quote args in such a way that reflex will read them correctly
	local q="'" qq="'\"'\"'"
	set -- "${@//$q/$qq}"
	set -- "${@/#/$q}"
	set -- "${@/%/$q}"
	REPLY="$*"
}

glob2re() {
	# Convert a glob to a regex, w/globstar (**) support
	local i c re=
	for (( i=0; i<${#1}; i++ )); do
		c=${1:$i:1}
		case $c in
		[!$^+.\(\)=!|?*]) re+=$c ;;
		[$^+.\(\)=!|]) re+=\\$c ;;
		"?") re+='[^/]' ;;
		"*")
			if [[ ${1:$i} =~ [*][*](/|$) ]] && { ! ((i)) || [[ ${1:$i-1:1} == '/' ]]; }; then
				re+='(([^/]*(/|$))*)'; i+=2   # skip '*/'
			else re+='[^/]*'
			fi
			;;
		*) re+=$c ;;
		esac
	done
	REPLY=$re
}

# We use the tty module for pager and such
dk use: tty

watch-reload .dkrc	# automatically re-run watch if configuration changes