Tiny searchpath for loading Lua script by Lua V5.1.4

main.lua

local searchpath_lua = require('searchpath_lua')
local filename = searchpath_lua("test")
print(filename)

searchpath_lua.lua

local split_str = function(str, sep)
    local tbl = {}
    local start_i = 1
    for i = start_i, string.len(str) do
        if str:sub(i,i) == sep then
            table.insert(tbl, string.sub(str, start_i, i - 1))
            start_i = i + 1
        end
    end
    return tbl
end

local LUA_PATH_SEP = ""
local LUA_PATH_MARK = ""
local DIR_SEP = ""
local set_consts = function()
    local tbl = split_str(package.config, "\n")
    for k, v in pairs(tbl) do
        if k == 1 then
            DIR_SEP = v
        end

        if k == 2 then
            LUA_PATH_SEP = v
        end

        if k == 3 then
            LUA_PATH_MARK = v
        end
    end
end

local readable = function(filename)
    local f = io.open(filename, "r")
    if f == nil then
        return false
    end
    f:close()
    return true
end

local get_luapaths = function()
    return split_str(package.path, LUA_PATH_SEP)
end

return function(name)
    set_consts()
    name = string.gsub(name, "%.", DIR_SEP)
    for _, path in pairs(get_luapaths()) do
        local filename = string.gsub(path, "%" .. LUA_PATH_MARK, name)
        if readable(filename) then
            return filename
        end
    end
end