diff --git a/bench.lua b/bench.lua
index 315b8f3e979b50cd68f7bf8001a35f8adcca03aa..81691d953b16a4f2c0f2ebe41ad5048047b50db0 100644
--- a/bench.lua
+++ b/bench.lua
@@ -2,20 +2,28 @@ if not ngx or not jit then
   error('must run in resty-cli with LuaJIT')
 end
 
+--[[
+local v = require "jit.v"
+v.on("/tmp/dump.log")
+--]]
+
 -------------
 -- Settings
 -------------
 local n_uuids = 1e6
 local p_valid_uuids = 70
 
-package.path = 'lib/?.lua;'..package.path
+package.path = 'lib/?.lua;' .. package.path
 
-local cuuid = require 'lua_uuid'
-local lua_uuid = require 'uuid'
-local ffi_uuid = require 'resty.uuid'
+local cuuid       = require 'lua_uuid'
+local lua_uuid    = require 'uuid'
+local ffi_uuid    = require 'resty.uuid'
 local luajit_uuid = require 'resty.jit-uuid'
+
 package.loaded['resty.jit-uuid'] = nil
+
 ngx.config.nginx_configure = function() return '' end
+
 local luajit_uuid_no_pcre = require 'resty.jit-uuid'
 
 math.randomseed(os.time())
@@ -23,6 +31,8 @@ math.randomseed(os.time())
 ---------------------
 -- UUID v4 generation
 ---------------------
+
+
 local tests = {
   ['C binding     '] = cuuid,
   ['Pure Lua      '] = lua_uuid.new,
@@ -30,8 +40,11 @@ local tests = {
   ['FFI binding   '] = ffi_uuid.generate_random
 }
 
+
 local v4_results = {}
 local time_reference
+
+
 for k, uuid in pairs(tests) do
   collectgarbage()
 
@@ -47,37 +60,47 @@ for k, uuid in pairs(tests) do
   end
 end
 
+
 for _, res in ipairs(v4_results) do
   res.diff = ((res.time - time_reference)/time_reference)*100
 end
 
+
 table.sort(v4_results, function(a, b) return a.time < b.time end)
 
+
 print(string.format('%s with %g UUIDs', jit.version, n_uuids))
 print('UUID v4 (random) generation')
 for i, result in ipairs(v4_results) do
-  print(string.format('%d. %s\ttook:\t%fs\t%+d%%', i, result.module, result.time, result.diff))
+  print(string.format('%d. %s\ttook:\t%fs\t%+d%%', i, result.module,
+                      result.time, result.diff))
 end
 
+
 ---------------------
 -- UUID v3 generation
 ---------------------
 
+
 -- unique names, unique namespaces: no strings interned
-tests = {
+local tests = {
   ['resty-jit-uuid'] = assert(luajit_uuid.factory_v3('cc7da0b0-0743-11e6-968a-bfd4d8c62f62'))
 }
+
+
 local names = {}
 for i = 1, n_uuids do
   names[i] = ffi_uuid.generate_random()
 end
 
+
 local v3_results = {}
+
+
 for k, factory in pairs(tests) do
   collectgarbage()
 
   local tstart = os.clock()
-  local check = {}
   for i = 1, n_uuids do
     factory(names[i])
   end
@@ -86,32 +109,40 @@ for k, factory in pairs(tests) do
   v3_results[#v3_results+1] = {module = k, time = time}
 end
 
+
 table.sort(v3_results, function(a, b) return a.time < b.time end)
 
+
 print('\nUUID v3 (name-based and MD5) generation if supported')
 for i, result in ipairs(v3_results) do
   print(string.format('%d. %s\ttook:\t%fs', i, result.module, result.time))
 end
 
+
 ---------------------
 -- UUID v5 generation
 ---------------------
 
+
 -- unique names, unique namespaces: no strings interned
-tests = {
+local tests = {
   ['resty-jit-uuid'] = assert(luajit_uuid.factory_v5('1b985f4a-06be-11e6-aff4-ff8d14e25128'))
 }
+
+
 local names = {}
 for i = 1, n_uuids do
   names[i] = ffi_uuid.generate_random()
 end
 
+
 local v5_results = {}
+
+
 for k, factory in pairs(tests) do
   collectgarbage()
 
   local tstart = os.clock()
-  local check = {}
   for i = 1, n_uuids do
     factory(names[i])
   end
@@ -120,56 +151,81 @@ for k, factory in pairs(tests) do
   v5_results[#v5_results+1] = {module = k, time = time}
 end
 
+
 table.sort(v5_results, function(a, b) return a.time < b.time end)
 
+
 print('\nUUID v5 (name-based and SHA-1) generation if supported')
 for i, result in ipairs(v5_results) do
   print(string.format('%d. %s\ttook:\t%fs', i, result.module, result.time))
 end
 
+
 -------------
 -- Validation
 -------------
-tests = {
+
+
+local tests = {
   ['FFI binding                      '] = ffi_uuid.is_valid,
   ['resty-jit-uuid (JIT PCRE enabled)'] = luajit_uuid.is_valid,
   ['resty-jit-uuid (Lua patterns)    '] = luajit_uuid_no_pcre.is_valid
 }
 
+
 local uuids = {}
 local p_invalid_uuids = p_valid_uuids + (100 - p_valid_uuids) / 2
+
+
 for i = 1, n_uuids do
   local r = math.random(0, 100)
+
   if r <= p_valid_uuids then
     uuids[i] = ffi_uuid.generate_random()
+
   elseif r <= p_invalid_uuids then
     uuids[i] = '03111af4-f2ee-11e5-ba5e-43ddcc7efcdZ' -- invalid UUID
+
   else
     uuids[i] = '03111af4-f2ee-11e5-ba5e-43ddcc7efcd' -- invalid length
   end
 end
 
+
 local valid_results = {}
+
+
 for k, validate in pairs(tests) do
   collectgarbage()
-  local tstart = os.clock()
+
   local check = {}
+  local tstart = os.clock()
+
   for i = 1, n_uuids do
     local ok = validate(uuids[i])
     check[ok] = true
   end
+
   -- make sure there is no false positives here
   if not check[true] or not check[false] then
     error('all validations have the same result for '..k)
   end
-  valid_results[#valid_results+1] = {module = k, time = os.clock() - tstart}
+
+  valid_results[#valid_results+1] = {
+    module = k,
+    time = os.clock() - tstart
+  }
 end
 
+
 table.sort(valid_results, function(a, b) return a.time < b.time end)
 
+
 print(string.format('\nUUID validation if supported (set of %d%% valid, %d%% invalid)',
   p_valid_uuids,
   100 - p_valid_uuids))
+
 for i, result in ipairs(valid_results) do
-  print(string.format('%d. %s\ttook:\t%fs', i, result.module, result.time))
+  print(string.format('%d. %s\ttook:\t%fs', i,
+        result.module, result.time))
 end
diff --git a/lib/resty/jit-uuid.lua b/lib/resty/jit-uuid.lua
index 240a8cdf089169afe846bdc70d362df7141333f6..e693cf3f3183662787eab518721c7bb07cad3804 100644
--- a/lib/resty/jit-uuid.lua
+++ b/lib/resty/jit-uuid.lua
@@ -149,7 +149,7 @@ do
     -- local u1 = uuid()             ---> __call metamethod
     -- local u2 = uuid.generate_v4()
     function _M.generate_v4()
-        return fmt('%s%s%s%s-%s%s-%s%s-%s%s-%s%s%s%s%s%s',
+        return (fmt('%s%s%s%s-%s%s-%s%s-%s%s-%s%s%s%s%s%s',
                     tohex(random(0, 255), 2),
                     tohex(random(0, 255), 2),
                     tohex(random(0, 255), 2),
@@ -169,7 +169,7 @@ do
                     tohex(random(0, 255), 2),
                     tohex(random(0, 255), 2),
                     tohex(random(0, 255), 2),
-                    tohex(random(0, 255), 2))
+                    tohex(random(0, 255), 2)))
     end
 end
 
@@ -282,13 +282,13 @@ do
 
                 local hash, ver, var = hash_fn(concat(buf, ''), name)
 
-                return fmt('%s-%s-%s%s-%s%s-%s', sub(hash, 1, 8),
+                return (fmt('%s-%s-%s%s-%s%s-%s', sub(hash, 1, 8),
                                                 sub(hash, 9, 12),
                                                 ver,
                                                 sub(hash, 15, 16),
                                                 var,
                                                 sub(hash, 19, 20),
-                                                sub(hash, 21, 32))
+                                                sub(hash, 21, 32)))
             end
         end