LFS lua example Lua 5.3 compatibility

lua_examples/lfs/_init.lua

@@ -8,10 +8,10 @@
   module related initialisaion in this. This example uses standard Lua features to
   simplify the LFS API.
 
-  The first section adds a 'LFS' table to _G and uses the __index metamethod to
-  resolve functions in the LFS, so you can execute the main function of module
-  'fred' by executing LFS.fred(params), etc. It also implements some standard
-  readonly properties:
+  For Lua 5.1, the first section adds a 'LFS' table to _G and uses the __index
+  metamethod to resolve functions in the LFS, so you can execute the main
+  function of module 'fred' by executing LFS.fred(params), etc.
+  It also implements some standard readonly properties:
 
   LFS._time    The Unix Timestamp when the luac.cross was executed.  This can be
                used as a version identifier.
@@ -24,11 +24,15 @@
                  print(table.concat(LFS._list,'\n'))
                gives you a single column listing of all modules in the LFS.
 
+   For Lua 5.3 LFS table is populated by the LFS implementation in C so this part
+   of the code is skipped.
 ---------------------------------------------------------------------------------]]
 
 local index = node.flashindex
-
-local lfs_t = {
+local G=_ENV or getfenv()
+local lfs_t
+if _VERSION == 'Lua 5.1' then
+    lfs_t = {
     __index = function(_, name)
         local fn_ut, ba, ma, size, modules = index(name)
         if not ba then
@@ -49,11 +53,15 @@ local lfs_t = {
     __newindex = function(_, name, value) -- luacheck: no unused
         error("LFS is readonly. Invalid write to LFS." .. name, 2)
       end,
-
     }
 
-local G=getfenv()
-G.LFS = setmetatable(lfs_t,lfs_t)
+    setmetatable(lfs_t,lfs_t)
+    G.module       = nil    -- disable Lua 5.0 style modules to save RAM
+    package.seeall = nil
+else
+    lfs_t = node.LFS
+end
+G.LFS = lfs_t
 
 --[[-------------------------------------------------------------------------------
   The second section adds the LFS to the require searchlist, so that you can
@@ -67,18 +75,9 @@ G.LFS = setmetatable(lfs_t,lfs_t)
 ---------------------------------------------------------------------------------]]
 
 package.loaders[3] = function(module) -- loader_flash
-  local fn, ba = index(module)
-  return ba and "Module not in LFS" or fn
+  return lfs_t[module]
 end
 
---[[-------------------------------------------------------------------------------
-  You can add any other initialisation here, for example a couple of the globals
-  are never used, so setting them to nil saves a couple of global entries
----------------------------------------------------------------------------------]]
-
-G.module       = nil    -- disable Lua 5.0 style modules to save RAM
-package.seeall = nil
-
 --[[-------------------------------------------------------------------------------
   These replaces the builtins loadfile & dofile with ones which preferentially
   loads the corresponding module from LFS if present.  Flipping the search order
@@ -97,5 +96,3 @@ G.dofile = function(n)
   local fn, ba   = index(mod)
   if ba or (ext ~= 'lc' and ext ~= 'lua') then return df(n) else return fn() end
 end
-
-

tools/luacheck_config.lua

@@ -430,6 +430,16 @@ stds.nodemcu_libs = {
             MEDIUM_PRIORITY = empty,
             HIGH_PRIORITY = empty
           }
+        },
+        LFS = {
+          read_only = true, 
+          fields = {
+            config = empty,
+            get = empty,
+            list = empty,
+            reload = empty,
+            time = empty
+          }
         }
       }
     },
@@ -919,7 +929,8 @@ stds.nodemcu_libs = {
     pack = empty,
     unpack  = empty,
     size = empty,
-    package = {fields = {seeall = read_write}}
+    package = {fields = {seeall = read_write}},
+    _ENV = empty
   }
 }