A simple function to detect Lua version

luaversion.lua

local luaversion = function()
    if ({false, [1] = true})[1] then   -- luacheck: ignore 314
        return 'LuaJIT'
    elseif 1 / 0 == 1 / '-0' then
        return 0 + '0' .. '' == '0' and 'Lua 5.4' or 'Lua 5.3'
    end
    local f = function() return function() end end
    return f() == f() and 'Lua 5.2' or 'Lua 5.1'
end

return {
    luaversion = luaversion,
}

test.sh

#!/bin/sh
if ! command -V hererocks > /dev/null; then
    echo 'hererocks not found'
    exit 1
fi
echo "using $(hererocks --version)"
echo

tmp=$(mktemp -d)
trap 'rm -r "${tmp}"; trap - EXIT' EXIT INT QUIT TERM HUP

for lua in 'lua 5.1' 'lua 5.2' 'lua 5.3' 'lua 5.4' 'luajit 2.0' 'luajit 2.1'; do
    echo "installing ${lua}"
    lua_dir="${tmp}/$(echo "${lua}" | tr ' .' '_')"
    if ! install_log=$(eval hererocks "--${lua}" "${lua_dir}" 2>&1); then
        echo "failed to install ${lua}:"
        echo "${install_log}"
        exit 1
    fi
    lua_bin="${lua_dir}/bin/lua"
    echo "installed $(${lua_bin} -v 2>&1)"
    echo "_VERSION = $("${lua_bin}" -e 'print(_VERSION)')"
    echo "luaversion() = $("${lua_bin}" -e 'print(require("luaversion").luaversion())')"
    echo
done

luaversion.lua is based on Egor Skriptunoff's script: http://lua-users.org/lists/lua-l/2016-05/msg00297.html

---

test.sh output:

using Hererocks 0.22.0

installing lua 5.1
installed Lua 5.1.5  Copyright (C) 1994-2012 Lua.org, PUC-Rio
_VERSION = Lua 5.1
luaversion() = Lua 5.1

installing lua 5.2
installed Lua 5.2.4  Copyright (C) 1994-2015 Lua.org, PUC-Rio
_VERSION = Lua 5.2
luaversion() = Lua 5.2

installing lua 5.3
installed Lua 5.3.5  Copyright (C) 1994-2018 Lua.org, PUC-Rio
_VERSION = Lua 5.3
luaversion() = Lua 5.3

installing lua 5.4
installed Lua 5.4.0  Copyright (C) 1994-2020 Lua.org, PUC-Rio
_VERSION = Lua 5.4
luaversion() = Lua 5.4

installing luajit 2.0
installed LuaJIT 2.0.5 -- Copyright (C) 2005-2017 Mike Pall. http://luajit.org/
_VERSION = Lua 5.1
luaversion() = LuaJIT

installing luajit 2.1
installed LuaJIT 2.1.0-beta3 -- Copyright (C) 2005-2017 Mike Pall. http://luajit.org/
_VERSION = Lua 5.1
luaversion() = LuaJIT