Clarification of usage of the user define tvar.lua and tables

function initPots()
    var.potVars = var.potVars or {}
    local next = next
    initVars = {}
    var.initVars = {heal = "martini", healnum = 5, threshold = 5}
	if next (var.potVars) ~= nil then
		if clrNum == "true" then  -- code to determine whether to just initalise healnum
			for k,v in pairs (var.potVars) do 
				if string.sub(string.lower(k),5,7) == "num" then
					v = 0  -- this worked but doing var.potVars.k = 0 didn't.
					print(k,v)
					--print ("i ran")
				end --if
			end --for
		end --if
	else	
		var.potVars = var.initVars
	end --if
	var.potVars.heal = "test"  -- this does not assign a new value.
	print(var.potVars.heal)  --shows default value.
end --initPots

function savePots()
	var.potVars = var.potVars
end --savePots

var.potVars = nil

function savePots()
	var.potVars = var.potVars
end --savePots

{
  healnum = 5,
  heal = "martini",
  threshold = 5,
  }

"healnum"=5
"heal"="martini"
"threshold"=5

-- tvar.lua
-- ----------------------------------------------------------
-- Accessing MUSHclient variables through the 'var' table.

-- See forum thread:
--  http://www.gammon.com.au/forum/?id=4904

-- Improvements suggested:
--  http://www.gammon.com.au/forum/?id=10980

-- Date: 6th Marh 2011

--[[

  * Set a variable by assigning something to it.
  * Delete a variable by assigning nil to it.
  * Get a variable by retrieving its value, will return nil if the variable does not exist.
  
  Improvements in this version:
  
  * Automatically turns things that look like numbers into numbers
  * Automatically turns "true" and "false" into booleans
  * Saves amd restores tables by using serialize
  
  Examples:

    require "tvar"
    
    var.target = "kobold"   -- set MUSHclient variable 'target' to kobold
    print (var.target)      -- print contents of MUSHclient variable

    -- table
    var.t1 = { "fish", "chips", "steak", { "subtable", "foo" }, drink = "beer" }
    
    
  Limitations:
  
    1. Things that look like numbers will become numbers, perhaps unintentionally
    2. Things that look like tables will become tables, perhaps unintentionally
    3. The words "true" and "false" will become booleans even if they were not before
    4. Slightly slower than the "var" module because of the extra tests
    
--]]

-- ----------------------------------------------------------

require "serialize"

var = {}  -- variables table

setmetatable (var, 
 { 
 -- called to access an entry
 __index = 
 function (t, key) 
 
  local v = GetVariable (key)  -- find the variable in MUSHclient variable space
  
  -- no such variable returns nil
  if v == nil then
     return nil
  end -- if

  -- convert true and false back into booleans
  if v == "true" then
    return true
  end -- if true

  if v == "false" then
    return false
  end -- if false
    
  -- if can be converted into a number return that number
  local n = tonumber (v)
  if n then 
    return n
  end -- if a number
  
  -- if variable is in the form {xxx} treat as a table
  if string.sub (v, 1, 1) == "{" and string.sub (v, -1, -1) == "}" then
    local t = {}  -- local environment
    local f = loadstring ("ret = " .. v)
    -- if loadstring fails, just return as a string
    if f then
      setfenv (f, t) -- local environment
      -- if pcall fails, just return as a string
      if pcall (f) then
        return t.ret
      end -- if executed ok
    end -- if loadstring worked
  end -- if looks like a table
  
  return v  -- return "normal" variable    
  
 end,  -- function __index
 
 -- called to change or delete an entry
 __newindex = 
  function (t, key, value) 
    local result  -- of SetVariable
    
    if value == nil then -- nil deletes it
      result = DeleteVariable (key)
    elseif type (value) == 'table' then
      result = SetVariable (key, serialize.save_simple (value))
    else
      result = SetVariable (key, tostring (value)) 
    end -- if
    
    -- warn if they are using bad variable keys
    if result == error_code.eInvalidObjectLabel then
     error ("Bad variable key '" .. key .. "'", 2)
    end  -- bad variable
  end  -- function __newindex
 })  -- end metatable
 
return var