#!/bin/sh
#
# Copyright (C) 2015-2016 William Ahern
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the "Software"),
# to deal in the Software without restriction, including without limitation
# the rights to use, copy, modify, merge, publish, distribute, sublicense,
# and/or sell copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
# DEALINGS IN THE SOFTWARE.
# ----------------------------------------------------------------------------
# DESCRIPTION
#
# runlua is a POSIX shell script for locating and invoking specific Lua
# interpreter versions. For example, the environment's Lua 5.1 interpreter
# might be named lua, lua5.1, lua51, luajit, luajit2.0.2, etc. runlua
# automates this difficult task in a safe, portable manner. runlua is
# regularly tested on Linux, OS X, Solaris, AIX, FreeBSD, NetBSD, and
# OpenBSD. And runlua safely handles all special characters encountered in
# option arguments, directory and command paths, and shell variables.
#
# To execute a simple statement in either a Lua 5.2 or 5.3 interpreter:
#
#   runlua -r5.2-5.3 -e "print(_VERSION)"
#
# The command-line options to runlua are a superset of the standard Lua
# interpreter. Run `runlua -h` for a description of each option.
#
# Shebang (#!) Execution
#
# In addition to explicit invocation, runlua supports two modes of shebang
# execution:
#
#   #!/path/to/runlua -r5.2
#   print"running Lua code!"
#
# and
#
#   #!/bin/sh
#   _=[[
#     echo "running shell code!"
#     exec runlua -r5.2 "$0" "$@"
#   ]]
#   print "running Lua code!"
#
# Only Linux and OS X support the first mode. The second is portable in
# practice--although POSIX does not require sh to be located at
# /bin/sh, it nonetheless can be invoked from that location on all the
# environments I've tested. And POSIX effectively requires shells to parse
# and execute scripts command-by-command, so no shell should read past the
# exec line.
#
# Also, the first mode requires a fully qualified path name, whereas with
# the second mode the shell code in the header could locate runlua
# dynamically. For example, a regression or example script in a project
# repository might have a header like
#
#   #!/bin/sh
#   _=[[
#     PATH="${PATH}:$(dirname "$0")/../bin"
#     exec "$(dirname "$0")/../contrib/runlua" "$0" "$@"
#   ]]
#   local mymodule = require"mymodule"
#   -- ...
#
# which will work regardless of the current working directory when invoking
# the script.
# ----------------------------------------------------------------------------
# PORTING NOTES
#
# unset) On NetBSD (confirmed up to 6.1.5) unset NAME will exit with a
#   failure status if no such variable is set. If errexit (set -e) is
#   enabled then the shell will exit. See NetBSD PR 49595.
#
# #!) Linux and OS X permit recursive shebang execution, which some users
#   might wish to take advantage of. However, neither will field-split
#   interpreter arguments, instead passing the remainder of the shebang line
#   as a single positional argument. So we manually field-split any first
#   argument.
#
#   Solaris (confirmed 11.1), AIX (confirmed 7.1), OpenBSD (confirmed 5.5),
#   NetBSD (confirmed 5.1.2, 6.1.1), and FreeBSD (confirmed 9.0) will search
#   for the interpreter recursively, following shebang interpreter paths
#   until a binary interpreter is found. But they will not add each
#   intervening interpreter path to the positional argument list. If you
#   don't know the paths you cannot execute them recursively.
#
# $@) On some BSD shells (confirmed NetBSD 5.1.2, 6.1.1, OpenBSD 5.5)
#   expansion of an empty $@ will wrongly trigger an error if nounset (set
#   -u) is in effect.
#
# noclobber) On some BSD shells (confirmed NetBSD 5.1.2, 6.1.1) the
#   noclobber (set -C) option will wrongly cause redirection to /dev/null
#   using the redirect operator (">") to fail. Use the appending redirect
#   operator (">>") as a workaround.
#
# trap EXIT) ksh88 (confirmed AIX 7.1) wrongly executes an EXIT trap when
#   the calling function returns, rather than when the shell exits. Note
#   ksh93 does not exhibit this bug.
#
# $@ and null IFS) ksh88 (confirmed AIX 7.1) pdksh (confirmed pdksh 5.2.14)
#   and pdksh derivatives (confirmed OpenBSD 5.6 ksh, NetBSD 6.1 ksh) will
#   expand $@ as a single field if IFS is null (set but empty). As a
#   workaround we set IFS to a control character when juggling paths. ksh93,
#   bash, and ash correctly expand $@ when IFS is null.
#
set -e # strict error
set -u # don't expand unbound variable
set -f # disable pathname expansion
set -C # noclobber

unset IFS
"unalias" -a

_LC_ALL="${LC_ALL+X}${LC_ALL-}"
export LC_ALL=C

: ${PATH:=$(command -p getconf PATH)}
: ${TMPDIR:=/tmp}

: ${RUNLUA_E:=}
: ${RUNLUA_R:=1-}
: ${RUNLUA_J:=0-}
: ${RUNLUA_M:=6}
: ${RUNLUA_S:=}
: ${RUNLUA_T:=}
: ${RUNLUA_D:=}
: ${RUNLUA_P:=}

MYVERSION=20160816
MYVENDOR="william@25thandClement.com"

TMPWD=

warn() {
	if [ "${RUNLUA_D#!}" -gt 0 -a -t 2 ]; then
		printf "\033[0;31m%s: %.0s${1}\033[0m\n" "${0##*/}" "$@" >&2
	else
		printf "%s: %.0s${1}\n" "${0##*/}" "$@" >&2
	fi
}

panic() {
	warn "$@"
	exit 1
}

debug() {
	if [ "${RUNLUA_D#!}" -gt 0 ]; then
		printf "%s: %.0s${1}\n" "${0##*/}" "$@" >&2
	fi
}

dump() {
	if [ "${RUNLUA_D#!}" -gt 1 ]; then
		printf "%s: %.0s${1}\n" "${0##*/}" "$@" >&2
	fi
}

# see porting note "$@ and null IFS"
null_ifs() {
	IFS=
	set -- x y z
	set -- "$@"
	unset IFS
	[ $# -gt 1 ] || printf "\2"
}

# glob PATTERN [MAXDEPTH] [EXEC-COMMAND] [INTERNAL:GLOB-COUNT]
#
# Recursive tree descending pathname generator combining features of glob(3)
# and find(3).
#
glob() {
        glob_N="${4:-0}"

        IFS=
        set +f
        for glob_F in ${1}; do
                [ -e "${glob_F}" ] || continue
                if eval "${3:-printf '%s\\n'} \"\${glob_F}\""; then
                        glob_N=$((${glob_N} + 1))
                fi
        done
        set -f
        unset IFS

        if [ "${2-0}" -gt 0 ]; then
                glob "${1%/*}/*/${1##*/}" "$((${2} - 1))" "${3:-}" "${glob_N}" || :
        fi

        [ "${glob_N}" -gt 0 ]
}

tempnam() {
	printf "%s-%s\n" "${1}" "$(od -An -N8 -tx1 -v /dev/urandom 2>>/dev/null | tr -cd '0123456789abcdef')"
}

# chomp VARIABLE SUFFIX
chomp() {
	chomp_K="${1}"
	chomp_C="${2}"

	eval "chomp_V=\"\${${chomp_K}}\""
	while [ "${chomp_V%${chomp_C}}" != "${chomp_V}" ]; do
		chomp_V="${chomp_V%${chomp_C}}"
	done
	eval "${chomp_K}=\"\${chomp_V}\""
}

# istrue STRING
istrue() {
	case "${1#!}" in
	[TtYy1]*)
		return 0
		;;
	*)
		return 1
		;;
	esac
}

# isinteger STRING
isinteger() {
	I="${1}"

	[ "${#I}" -gt 0 ] || return 1

	while [ "${#I}" -gt 0 ]; do
		[ "${I##[0123456789]}" != "${I}" ] || return 1
		I="${I##[0123456789]}"
	done
}

# isdir PATH
isdir() {
	[ "${#1}" -gt 0 ] && [ -d "${1}" ]
}

# ver2num STRING [MAJOR] [MINOR] [PATCH]
ver2num() {
	M="${2:-0}"
	m="${3:-0}"
	p="${4:-0}"

	IFS="."
	set -- ${1}
	unset IFS

	if isinteger "${1:-}"; then
		M=${1}
	fi

	if isinteger "${2:-}"; then
		m=${2}
	fi

	if isinteger "${3:-}"; then
		p=${3}
	fi

	printf "$((${M} * 10000 + ${m} * 100 + ${p}))\n"
}

num2ver() {
	M=$((${1} / 10000 % 100))
	m=$((${1} / 100 % 100))
	p=$((${1} % 100))
	printf "${M}.${m}.${p}\n"
}

api2num() {
	n="$(ver2num "$@")"
	printf "$((${n} / 100))\n"
}

num2api() {
	printf "$((${1} / 100 % 100)).$((${1} % 100))\n"
}

getapi() {
	if [ -x "${1}" ]; then
		api2num "$(noenv; cdwd; "${1}" -e 'print(string.match(_VERSION, [[[%d.]+]]))' </dev/null 2>>/dev/null || true)"
	fi
}

getrel() {
	if [ -x "${1}" ]; then
		ver2num "$(noenv; cdwd; "${1}" -v </dev/null 2>&1 | sed -ne 's/^Lua[^ ]* \([0-9][0-9\.]*\).*/\1/p' | head -n1)"
	fi
}

trypth() {
	trypth_LUA="${1}"
	shift 1
	for L; do
		dump "testing LD_PRELOAD=\"%s\" %s" "${L}" "${trypth_LUA}"
		# glibc's ld.so ignores LD_PRELOAD errors. It does emit a
		# diagnostic to stderr, so we redirect stderr to stdout so
		# that it corrupts our expected output.
		#
		# NB: musl's ld.so ignores LD_PRELOAD errors, but never
		# issues a diagnostic. There's no way to distinguish success
		# and failure.
		TMP="$(noenv; cdwd; LD_PRELOAD="${L}" "${trypth_LUA}" -e 'print"OK"' </dev/null 2>&1 || true)"
		[ "${TMP}" = "OK" ] && printf "%s\n" "${L}" && return 0
		dump "unable to preload %s (expected 'OK', got '%s')" "${L}" "$(printf "%s" "${TMP}" | tr '\n' ' ')"
	done

	return 1
}

getpth() {
	case "${getpth_UNAME:=$(uname -s)}" in
	Linux)
		# Linux/glibc supports loading libpthread through a DSO, but
		# glibc has several bugs, including a race in libdl.
		#
		# Linux/musl unifies libpthread with libc. But it's a noop
		# to preload libpthread.so.0 so we don't bother trying to
		# distinguish musl.
		set +f
		trypth "${1}" "libpthread.so.0" /lib/*/libpthread.so* /lib/libpthread.so* && return 0
		set -f
		;;
	FreeBSD|NetBSD|OpenBSD)
		# Neither FreeBSD, NetBSD, nor OpenBSD support loading
		# libpthread through a DSO. NetBSD requires a full path.
		set +f
		trypth "${1}" "libpthread.so" /usr/lib/libpthread.so* && return 0
		set -f
		;;
	*BSD*)
		# Assume other BSDs are similar and make a best effort.
		set +f
		trypth "${1}" "libpthread.so" /usr/lib/libpthread.so* && return 0
		set -f

		debug "skipping libpthread preloading (unknown operating system: %s)" "${getpth_UNAME}"
		return 0
		;;
	Darwin)
		# libpthread.dylib integrated with libSystem.dylib
		return 0
		;;
	SunOS)
		# libpthread integrated with libc since Solaris 10
		getpth_V="$(ver2num "$(uname -v)")"
		getpth_M="$(ver2num "10")"
		[ ${getpth_V} -ge ${getpth_M} ] && return 0

		trypth "${1}" "libpthread.so" && return 0
		;;
	oops)
		# for regression testing
		;;
	*)
		debug "skipping libpthread preloading (unknown operating system: %s)" "${getpth_UNAME}"
		return 0
		;;
	esac

	panic "unable to locate libpthread"
}

cdwd() {
	if [ ${#TMPWD} -gt 0 ]; then
		cd "${TMPWD}"
	fi
}

mkwd() {
	if [ -d "/dev" -a ! -w "/dev" ]; then
		TMPWD="/dev"
		debug "reusing /dev as non-writable working directory"
	else
		TMPWD="$(tempnam "${TMPDIR}/${0##*/}")"
		debug "creating non-writable working directory %s" "${TMPWD}"
		mkdir -m0500 "${TMPWD}"
	fi
}

trap "rmwd" EXIT # see portability note "trap EXIT"

rmwd() {
	if [ ${#TMPWD} -gt 0 -a "${TMPWD}" != "/dev" -a -d "${TMPWD}" ]; then
		debug "removing working directory %s" "${TMPWD}"
		rmdir -- "${TMPWD}"
		TMPWD=
	fi
}

# set LUA_API and LUA_PRELOAD if LUA was specified from environment
checklua() {
	case "${LUA_API:-}" in
	[0123456789].[0123456789])
		;;
	*)
		# need absolute path
		if [ "${LUA#*/}" = "${LUA}" ]; then
			LUA="$(command -v "${LUA}" || panic "%s: cannot find path" "${LUA}")"
			debug "using %s" "${LUA}"
		fi
		V="$(getapi "${LUA}")"
		LUA_API="$(num2api ${V:-0})"
		debug "%s API is %s" "${LUA}" "${LUA_API}"
		;;
	esac

	if istrue "${RUNLUA_T}"; then
		if ! istrue "${LUA_PRELOAD+true}"; then
			LUA_PRELOAD="$(getpth "${LUA}")"
			[ -z "${LUA_PRELOAD}" ] || debug "preloading %s" "${LUA_PRELOAD}"
		fi
	fi
}

findlua() {
	if [ -n "${LUA:-}" ]; then
		checklua
		printf "%s\n" "${LUA}"
		return 0
	fi

	mkwd

	TMP="${RUNLUA_R#!}"
	find_API_MIN="$(api2num "${TMP%%[,:-]*}" 1 0)"
	find_API_MAX="$(api2num "${TMP##*[,:-]}" 99 99)"
	TMP="${RUNLUA_R#!}"
	find_REL_MIN="$(ver2num "${TMP%%[,:-]*}" 1 0 0)"
	find_REL_MAX="$(ver2num "${TMP##*[,:-]}" 99 99 99)"
	TMP="${RUNLUA_J#!}"
	find_JIT_MIN="$(ver2num "${TMP%%[,:-]*}" 1 0 0)"
	find_JIT_MAX="$(ver2num "${TMP##*[,:-]}" 99 99 99)"

	found_PATH=
	found_API=0
	found_REL=0

	# leverage shell pathname expansion to locate interpreter by
	# iterating over $PATH directories and letting shell do the search
	IFS=:
	set -- ${PATH}
	unset IFS

	for D; do
		# get abspath because getapi and getrel cd to working directory
		D="$(! cd "${D}" 2>>/dev/null || pwd)"
		[ ${#D} -gt 0 ] || continue

		set -- "false" # see porting note "$@"

		IFS="${NULL_IFS="$(null_ifs)"}"
		set +f
		if [ ! $find_JIT_MIN -gt 0 ]; then # PUC Lua
			set -- "$@" ${D}/lu[a] ${D}/lua5* ${D}/lua-5*
		fi
		if [ $find_JIT_MAX -gt 0 ]; then # LuaJIT
			set -- "$@" ${D}/luajit*
		fi
		set -f
		unset IFS

		for F; do
			[ "${F}" != "false" ] || continue

			dump "testing %s" "${F}"

			# NB: match only a narrow range of basenames so we
			# don't execute something like luatex or lua-tool
			B="${F##*/}"

			# strip pre-release suffix from basename (luajit-2.1.0-alpha)
			B="${B%[._-]alpha*}"
			B="${B%[._-]beta*}"
			B="${B%[._-]dev*}"

			# strip version suffix from basename (lua51,  luajit-2.0.3)
			while [ "${B}" != "${B%%[0123456789._-]}" ]; do
				B="${B%%[0123456789._-]}"
			done

			# skip if basename isn't "lua" or "luajit"
			[ "${B}" = "lua" ] || [ "${B}" = "luajit" ] || continue

			V="$(getapi "${F}")"
			R="$(getrel "${F}")"
			: ${V:=0}
			: ${R:=0}

			debug "%s is version %s (%s API)" "${F}" "$(num2ver "${R}")" "$(num2api "${V}")"

			# does it meet our API range criteria?
			[ ${V} -ge ${find_API_MIN} -a ${V} -le ${find_API_MAX} ] || continue

			# does it meet our release range criteria?
			if [ ${R} -lt ${find_REL_MIN} -o ${R} -gt ${find_REL_MAX} -o ${find_JIT_MIN} -gt 0 ]; then
				# try luajit release range
				[ "${B}" = "luajit" ] || continue
				[ ${R} -ge ${find_JIT_MIN} ] || continue
				[ ${R} -le ${find_JIT_MAX} ] || continue
			fi

			# is it a better fit than what we already found?
			[ ${V} -gt 0 -a ${V} -ge ${found_API} -a ${R} -gt ${found_REL} ] || continue

			# does it work if we preload libpthread?
			if istrue "${RUNLUA_T}"; then
				found_PTH="$(getpth "${F}")"
			else
				found_PTH=""
			fi

			found_PATH="${F}"
			found_API=${V}
			found_REL=${R}
		done
	done

	rmwd

	LUA="${found_PATH}"
	LUA_API="$(num2api "${found_API}")"
	LUA_PRELOAD="${found_PTH-}"

	[ -n "${LUA}" ] || panic "unable to locate Lua interpreter"

	debug "using %s" "${LUA}"
	[ -n "${LUA_PRELOAD}" ] && debug "preloading %s" "${LUA_PRELOAD}"

	printf "%s\n" "${LUA}"
}

# scan_api2key PREFIX VERSION
scan_api2key() {
	case "${2}" in
	5.1)
		printf "%s" "${1}"
		;;
	*)
		printf "%s_%s" "${1}" "$(printf "%s" "${2}" | tr '.' '_')"
		;;
	esac
}

scan_addenv() {
	[ "${#1}" -gt 0 ] || return 0

	addenv_K="$(scan_api2key "${2}" "${3}")"
	debug "adding %s to %s" "${1}" "${addenv_K}"

	# NB: append left to right (see note in scan routine)
	eval "addenv_V=\"\${${addenv_K}:-;;}\""
	addenv_V="${1};${addenv_V#;}"
	eval "export ${addenv_K}=\"\${addenv_V}\""
}

# callback from glob for paths matching */${LUA_API}
scan__add() {
	isdir "${1}" || return 0

	# NB: test in subshell as our glob routine isn't reentrant
	if (glob "${1}/*.lua" ${RUNLUA_M} ":"); then
		scan_addenv "${1}/?.lua" LUA_PATH "${LUA_API}"
	fi

	if (glob "${1}/*.so" ${RUNLUA_M} ":"); then
		scan_addenv "${1}/?.so" LUA_CPATH "${LUA_API}"
	fi
}

scan() {
	# NB: process from right to left and append left to right
	while [ ${#RUNLUA_S} -gt 0 ]; do
		scan_D="${RUNLUA_S##*;}"

		if isdir "${scan_D}"; then
			debug "scanning %s" "${scan_D}"
			glob "${scan_D}/${LUA_API}" "${RUNLUA_M}" scan__add || :
		fi

		RUNLUA_S="${RUNLUA_S%${scan_D}}"
		chomp RUNLUA_S ";"
	done
}

noenv() {
	for F in $(env | sed -ne 's/^\(LUA_C\{0,1\}PATH[_0123456789]*\).*$/\1/p' -e 's/^\(LUA_INIT[_0123456789]*\).*$/\1/p'); do
		unset "$F" || true # see porting note "unset"
	done
}

setopt() {
	setopt_VAR="${1}"
	setopt_NVAL="${2:-}"
	eval "setopt_OVAL=\"\${${setopt_VAR}:-}\""

	# don't set if value prefixed with "!"
	[ "${setopt_OVAL}" = "${setopt_OVAL#!}" ] || return 0

	eval "${setopt_VAR}=\"\${setopt_NVAL}\""
}

usage() {
	cat <<-EOF
	Usage: ${0##*/} [-e:il:vEr:j:Jms:tdpVh] [PATH [...]]
	  -e STRING  execute statement
	  -i         enter interactive mode after executing PATH
	  -l STRING  require package
	  -v         print interpreter version information
	  -E         ignore environment variables
	  -r RANGE   run specific Lua version
	  -j RANGE   run specific LuaJIT version
	  -J         exclude LuaJIT from candidate interpreters
	  -m NUMBER  limit recursion to NUMBER
	  -s PATH    scan directory tree for Lua modules
	  -t         preload POSIX threading library
	  -d         enable debug logging (twice for even more logging)
	  -p         print path of Lua interpreter
	  -V         print runlua version information
	  -h         print this usage message

	Examples:
	  -r5.2.1    only run PUC Lua 5.2.1 interpreter
	  -r5.1      run any Lua 5.1 interpreter, including LuaJIT
	  -r5.2-5.3  run any Lua 5.2 or 5.3 interpreter
	  -r5.2-     run any Lua 5.2 or later interpreter
	  -j2.1      only run LuaJIT 2.1 interpreter

	Environment:
	  RUNLUA_E=BOOLEAN  same as -E if TRUE
	  RUNLUA_R=RANGE    same as -r (use !RANGE to override -r)
	  RUNLUA_J=RANGE    same as -j (use !RANGE to override -j or -J)
	  RUNLUA_M=NUMBER   same as -m
	  RUNLUA_T=BOOLEAN  same as -t if TRUE
	  RUNLUA_D=NUMBER   set debug level (e.g. same -dd if 2)
	  RUNLUA_P=BOOLEAN  same as -p if TRUE

	Examples:
	  RUNLUA_R=5.2 runlua           run any Lua 5.2 interpreter
	  RUNLUA_R=5.3 runlua -r5.2     same as above (-r has higher precedence)
	  RUNLUA_R='!5.3' runlua -r5.2  run any Lua 5.3 interpreter (! overrides -r)

	BNF:
	  <PATH>    ::= <STRING>
	  <RANGE>   ::= <VERSION> | [VERSION] "-" [VERSION]
	  <VERSION> ::= <NUMBER> ["." <NUMBER> ["." <NUMBER>]]
	  <BOOLEAN> ::= <TRUE> | <FALSE>
	  <TRUE>    ::= "yes" | "true" | "1"
	  <FALSE>   ::= "no" | "false" | "0" | ""

	Report bugs to <william@25thandClement.com>
	EOF
}

version() {
	cat <<-EOF
	runlua  $MYVERSION
	vendor  $MYVENDOR
	release $MYVERSION
	EOF
}

#
# Field-split first argument. See porting note "#!".
#
# If we only have one argument than it's either a script path or we're not
# running as a shebang interpreter. If we have zero then we don't want to
# accidentally field-split the script path becaues it might contain spaces.
#
if [ $# -ge 2 ]; then
	TMP="${1}"
	shift 1
	IFS=" "
	set -- ${TMP} "$@"
	unset IFS
fi

ARGC=0
pusharg() {
	eval "ARG${ARGC}=\"\${1}\""
	ARGC=$((${ARGC} + 1))
}

while getopts "e:il:vEr:j:Js:tdpVh" OPTC; do
	case "${OPTC}" in
	e)
		pusharg "-e"
		pusharg "${OPTARG}"
		;;
	i)
		pusharg "-i"
		;;
	l)
		pusharg "-l"
		pusharg "${OPTARG}"
		;;
	v)
		pusharg "-v"
		;;
	E)
		setopt RUNLUA_E yes
		;;
	r)
		setopt RUNLUA_R "${OPTARG}"
		;;
	j)
		setopt RUNLUA_J "${OPTARG}"
		;;
	J)
		setopt RUNLUA_J "0-0"
		;;
	m)
		setopt RUNLUA_M "${OPTARG}"
		;;
	s)
		if [ "${RUNLUA_S}" = "${RUNLUA_S#!}" ]; then
			MAIN_S="${MAIN_S-}${MAIN_S:+;}${OPTARG}"
		fi
		;;
	t)
		setopt RUNLUA_T yes
		;;
	d)
		MAIN_D="$((${MAIN_D:-0} + 1))"
		;;
	p)
		setopt RUNLUA_P yes
		;;
	V)
		version
		exit 0
		;;
	h)
		usage
		exit 0
		;;
	*)
		usage >&2
		exit 1
		;;
	esac
done

shift $((${OPTIND} - 1))

#
# Prepend our argument stack to the positional list.
#
if [ ${ARGC} -gt 0 ]; then
	# first append to our positional list
	I=0
	while [ ${I} -lt ${ARGC} ]; do
		eval "ARG=\"\${ARG${I}}\""

		if [ $# -gt 0 ]; then
			set -- "$@" "${ARG}"
		else
			set -- "${ARG}"
		fi

		I=$(($I + 1))
	done

	# then rotate left
	I=0
	N=$(($# - ${ARGC}))
	while [ ${I} -lt ${N} ]; do
		set -- "$@" "${1}"
		shift 1

		I=$(($I + 1))
	done
fi

RUNLUA_M="${RUNLUA_M#!}"
isinteger "${RUNLUA_M}" || panic "%s: not an integer" "${RUNLUA_M}"

RUNLUA_S="${MAIN_S-}${MAIN_S:+;}${RUNLUA_S#!}"
chomp RUNLUA_S ";"

setopt RUNLUA_D "${MAIN_D:-0}"
isinteger "${RUNLUA_D#!}" || panic "%s: not an integer" "${RUNLUA_D#!}"

if istrue "${RUNLUA_E}"; then
	noenv
fi

findlua >>/dev/null

if istrue "${RUNLUA_P}"; then
	printf "%s\n" "${LUA}"
	exit 0
fi

scan

if [ ${#_LC_ALL} -gt 0 ]; then
	LC_ALL="${_LC_ALL#X}"
else
	unset LC_ALL
fi

if [ -n "${LUA_PRELOAD-}" ]; then
	export LD_PRELOAD="${LD_PRELOAD-}${LD_PRELOAD:+:}${LUA_PRELOAD}"
fi

# see portability note "$@"
if [ $# -gt 0 ]; then
	exec "${LUA}" "$@"
else
	exec "${LUA}"
fi