quick lua implementation of "random" UUID

lua-uuid.lua

local random = math.random
local function uuid()
    local template ='xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'
    return string.gsub(template, '[xy]', function (c)
        local v = (c == 'x') and random(0, 0xf) or random(8, 0xb)
        return string.format('%x', v)
    end)
end

Alternate solution without an auxiliary table: replace in the top function

return string.gsub(...)

with

local ans = string.gsub(...)
return ans

The first return value of string.gsub is assigned to ans, the others are ignored

@jrus Thank you for the snippet.

your can use this seed to avoid same uuid math.randomseed(tonumber(tostring(os.time()):reverse():sub(1, 9)))

I'd like to note, that this does not seem to work with lua 5.2.4. for i=1,10 do print(uuid()) end will print 10 times the same UUID. However, without the custom seed, it works perfectly fine.