run windows programs from WSL with path conversion and support running functions straight from cmd

wsl2exe

#!/bin/zsh
# execute Windows program from WSL shell
# where Windows paths are present, and
# converted to normal paths like for compact
#
# rename this script to anything besides wsl2exe
# to act as a proxy to the program you want to execute,
# as long as it refers to a program existing in PATH,
# and that windows PATH is added to the WSL instance

[ ! -f '/proc/sys/fs/binfmt_misc/WSLInterop' ] && {
	orig="$(which -a "${0:t}" | sed -n 2p)"
	[ -s "$orig" ] && exec -- "$orig" ${@} || {
		echo "Original command not found: ${0:t}"
	}
	exit
}

# don't append .exe to the command argument
COMMAND=""
[ "${0[-7,-1]:l}" = "wsl2exe" ] && {
	[ $# -eq 0 ] && { echo "Usage: wsl2exe [windows command] [args...]"; exit; }
	COMMAND="$1"
	shift
} || {
	ALLOW_BUILTINS=0 # ???? *
	COMMAND="$(basename "$0")"
}
declare -a ARGBUILDER
ARGBUILDER=()
# i just remembered, this will come from shell, not batch, dummy *
[ ${ALLOW_BUILTINS:-1} -eq 1 ] && {
	# (1) check for typed built in, to then turn into cmd /c
	# reserved names come first, i.e. to run dir.exe from
	# cygwin in the command line, it must be typed as "dir.exe"
	# otherwise windows built in is ran
	CMD_LOWER=${COMMAND:l}
	()(( $@[(Ie)$CMD_LOWER] )) \
		assoc cls copy date del dir dpath \
		echo ftype forfiles mklink pushd \
		popd set setlocal shift rem rmdir \
		start time title type ver vol && {
		got_builtin=1
		use_cmd=1
	}
}
[ ${got_builtin:-0} -eq 0 ] && {
	# if above isn't the case
	# (2) check paths for executables with following extensions
	j=0
	for i (com exe bat cmd) {
		exe="${COMMAND}.${i}"
		{ command -v "${exe}" &> /dev/null } && {
			COMMAND="${exe}"
			break
		}
	}
}
which wslpath >/dev/null 2>/dev/null && pathconv=wslpath || pathconv=cygpath
mountpoint=/mnt/
fix() {
	a="$1"
	# convert absolute linux paths to windows paths
	case "$a" in
		# uhhh https://learn.microsoft.com/en-us/windows/wsl/wsl-config#automount-settings
		/tmp/*)
			a="$($pathconv -a -w "${a:a:h}")\\${a:t}$([ -d "$a" ] && <<< \\)"
			;;
		$mountpoint*)
			#[ -e "$a" ] && {
				# TODO?: recursive check existence of upper and upper path
				[ -d "${a:a:h}" ] && {
					a="$($pathconv -a -m "${a:a:h}")${a:t}$([ -d "$a" ] && echo /)"
					[ ${NBS:-0} -eq 1 ] && a=$(sed 's/\//\\\\\\\\/g' - <<< "${a}") # brain damage
				}
			#}
			;;
		# point to rootfs for folders in wsl???
		/dev/null)
			# ignore for cygwin programs??
			a="NUL"
		;;
	esac
	<<< "${a}"
}
ext="${COMMAND##*.}"
[ ${ext} = bat -o ${ext} = cmd ] && use_cmd=1
[ ${use_cmd:-0} -eq 1 ] && {
	NBS=1 # NEED BACKSLASHES
	ARGBUILDER+=("/c" "$(fix "$CMD_LOWER")")
	COMMAND="cmd.exe"
}
# detect if running on WSL because I just
# hardlinked "compact" to here and wanted to
# use the script on Cygwin
# oops
# now want to use mp3_speedrun with this because bundows memory leak >:(
[ $# -gt 0 ] && for a in "$@"; do
	[ "{{$a}}" = "{{-}}" ] &&
		ARGBUILDER+=("-") || # so stupid
		ARGBUILDER+=("$(fix "$a")")
done
$COMMAND "${ARGBUILDER[@]}"