--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/share/lua/5.2/luarocks/persist.lua	Fri Dec 14 22:24:27 2012 +0000
@@ -0,0 +1,173 @@
+
+--- Utility module for loading files into tables and
+-- saving tables into files.
+-- Implemented separately to avoid interdependencies,
+-- as it is used in the bootstrapping stage of the cfg module.
+module("luarocks.persist", package.seeall)
+
+local util = require("luarocks.util")
+
+--- Load a Lua file containing assignments, storing them in a table.
+-- The global environment is not propagated to the loaded file.
+-- @param filename string: the name of the file.
+-- @param tbl table or nil: if given, this table is used to store
+-- loaded values.
+-- @return table or (nil, string): a table with the file's assignments
+-- as fields, or nil and a message in case of errors.
+function load_into_table(filename, tbl)
+   assert(type(filename) == "string")
+   assert(type(tbl) == "table" or not tbl)
+
+   local result, chunk, ran, err
+   local result = tbl or {}
+   if setfenv then -- Lua 5.1
+      chunk, err = loadfile(filename)
+      if chunk then
+         setfenv(chunk, result)
+         ran, err = pcall(chunk)
+      end
+   else -- Lua 5.2
+      chunk, err = loadfile(filename, "t", result)
+      if chunk then
+         ran, err = pcall(chunk)
+      end
+   end
+   
+   if not chunk then
+      if err:sub(1,5) ~= filename:sub(1,5) then
+         return false, err
+      end
+      return nil, "Error loading file: "..err
+   end
+   if not ran then
+      return nil, "Error running file: "..err
+   end
+   return result
+end
+
+local write_table
+
+--- Write a value as Lua code, invoking write_table.
+-- This function handles only numbers, strings and tables
+-- are keys (tables are handled recursively).
+-- @param out userdata: a file object, open for writing.
+-- @param v: the value to be written.
+-- @param level number: the indentation level
+-- @param sub_order table: optional prioritization table
+-- @see write_table
+local function write_value(out, v, level, sub_order)
+   if type(v) == "table" then
+      write_table(out, v, level + 1, sub_order)
+   elseif type(v) == "string" then
+      if v:match("\n") then
+         local open, close = "[[", "]]"
+         local equals = 0
+         while v:find(open,1,true) or v:find(close,1,true) do
+            equals = equals + 1
+            local eqs = ("="):rep(equals)
+            open, close = "["..eqs.."[", "]"..eqs.."]"
+         end
+         out:write(open.."\n"..v..close)
+      else
+         out:write("\""..v:gsub("\"", "\\\"").."\"")
+      end
+   else
+      out:write(tostring(v))
+   end
+end
+
+--- Write a table as Lua code representing a table to disk
+-- (that is, in curly brackets notation).
+-- This function handles only numbers, strings and tables
+-- are keys (tables are handled recursively).
+-- @param out userdata: a file object, open for writing.
+-- @param tbl table: the table to be written.
+-- @param level number: the indentation level
+-- @param field_order table: optional prioritization table
+write_table = function(out, tbl, level, field_order)
+   out:write("{")
+   local sep = "\n"
+   local indentation = "   "
+   local indent = true
+   local i = 1
+   for k, v, sub_order in util.sortedpairs(tbl, field_order) do
+      out:write(sep)
+      if indent then
+         for n = 1,level do out:write(indentation) end
+      end
+      sep = ",\n"
+      indent = true
+      if type(k) == "number" then
+         if k ~= i then
+            out:write("["..tostring(k).."]=")
+         else
+            i = i + 1
+         end
+         indent = false
+         sep = ", "
+      elseif type(k) == "table" then
+         out:write("[")
+         write_table(out, k, level + 1)
+         out:write("] = ")
+      else
+         if k:match("^[a-zA-Z_][a-zA-Z0-9_]*$") then
+            out:write(k.." = ")
+         else
+            out:write("['"..k:gsub("'", "\\'").."'] = ") 
+         end
+      end
+      write_value(out, v, level, sub_order)
+   end
+   if sep ~= "\n" then
+      out:write("\n")
+      for n = 1,level-1 do out:write(indentation) end
+   end
+   out:write("}")
+end
+
+--- Writes a table to an io-like object.
+-- @param out userdata: a file object, open for writing.
+-- @param tbl table: the table to be written.
+-- @param field_order table: optional prioritization table
+-- @return userdata The file object originally passed in as the `out` parameter.
+local function write_table(out, tbl, field_order)
+   for k, v, sub_order in util.sortedpairs(tbl, field_order) do
+      out:write(k.." = ")
+      write_value(out, v, 0, sub_order)
+      out:write("\n")
+   end
+   return out
+end
+
+--- Save the contents of a table to a string.
+-- Each element of the table is saved as a global assignment.
+-- Only numbers, strings and tables (containing numbers, strings
+-- or other recursively processed tables) are supported.
+-- @param tbl table: the table containing the data to be written
+-- @param field_order table: an optional array indicating the order of top-level fields.
+-- @return string
+function save_from_table_to_string(tbl, field_order)
+   local out = {buffer = {}}
+   function out:write(data) table.insert(self.buffer, data) end
+   write_table(out, tbl, field_order)
+   return table.concat(out.buffer)
+end
+
+--- Save the contents of a table in a file.
+-- Each element of the table is saved as a global assignment.
+-- Only numbers, strings and tables (containing numbers, strings
+-- or other recursively processed tables) are supported.
+-- @param filename string: the output filename
+-- @param tbl table: the table containing the data to be written
+-- @param field_order table: an optional array indicating the order of top-level fields.
+-- @return boolean or (nil, string): true if successful, or nil and a
+-- message in case of errors.
+function save_from_table(filename, tbl, field_order)
+   local out = io.open(filename, "w")
+   if not out then
+      return nil, "Cannot create file at "..filename
+   end
+   write_table(out, tbl, field_order)
+   out:close()
+   return true
+end