.

extra.lua

@@ -1,13 +1,13 @@
-function strpad(num, count, pad)
+local function strpad(num, count, pad)
     num = tostring(num)
     return (pad:rep(count)..num):sub(#num)
 end
 
-function add_zeros(num, count)
+local function add_zeros(num, count)
     return strpad(num, count - 1, '0')
 end
 
-function mixed_sorter(a, b)
+local function mixed_sorter(a, b)
     a = type(a) == 'number' and add_zeros(a, 16) or tostring(a)
     b = type(b) == 'number' and add_zeros(b, 16) or tostring(b)
     return a < b
@@ -15,7 +15,7 @@ end
 
 -- loosely based on http://lua-users.org/wiki/SortedIteration
 -- the original didn't make use of closures for who knows why
-function order_keys(t)
+local function order_keys(t)
     local oi = {}
     for key in pairs(t) do
         table.insert(oi, key)
@@ -24,7 +24,7 @@ function order_keys(t)
     return oi
 end
 
-function opairs(t, cache)
+local function opairs(t, cache)
     local oi = cache and cache[t] or order_keys(t)
     if cache then
         cache[t] = oi
@@ -36,3 +36,27 @@ function opairs(t, cache)
         if key then return key, t[key] end
     end
 end
+
+local function traverse(path)
+    if not path then return end
+    local parent = _G
+    local key
+    for w in path:gfind("[%w_]+") do
+        if key then
+            parent = rawget(parent, key)
+            if type(parent) ~= 'table' then return end
+        end
+        key = w
+    end
+    if not key then return end
+    return {parent=parent, key=key}
+end
+
+return {
+    strpad = strpad,
+    add_zeros = add_zeros,
+    mixed_sorter = mixed_sorter,
+    order_keys = order_keys,
+    opairs = opairs,
+    traverse = traverse,
+}

pt.lua

@@ -1,10 +1,11 @@
-require 'extra'
+local extra = require 'extra'
+local opairs = extra.opairs
 
 local pt = {}
 pt.__index = pt
 setmetatable(pt, pt)
 
-function rawstr(v)
+local function rawstr(v)
     if v == nil then return 'nil' end
     local mt = getmetatable(v)
     local ts = mt and rawget(mt, '__tostring')
@@ -15,11 +16,11 @@ function rawstr(v)
     return s
 end
 
-function getaddr(t)
+local function getaddr(t)
     return rawstr(t):sub(#type(t) + 3)
 end
 
-function copy(t)
+local function copy(t)
     -- shallow copy
     if type(t) ~= 'table' then return end
     local new = {}