/serialize.lua

  1----------------------------------------------------------------------------
  2-- Serialize tables.
  3-- It works only for tables without cycles and without functions or
  4-- userdata inside it.
  5-- @release $Id: serialize.lua 34 2010-04-19 21:18:00Z rpusztai $
  6----------------------------------------------------------------------------
  7
  8local ipairs, pairs, type = ipairs, pairs, type
  9local format = string.format
 10local sort, tinsert = table.sort, table.insert
 11
 12--
 13local value = nil
 14
 15----------------------------------------------------------------------------
 16-- Serializes a table.
 17-- @param tab Table representing the session.
 18-- @param outf Function used to generate the output.
 19-- @param ind String with indentation pattern (default = "").
 20-- @param pre String with indentation prefix (default = "").
 21----------------------------------------------------------------------------
 22local function tabledump (tab, outf, ind, pre)
 23	local sep_n, sep, _n = ",\n", ", ", "\n"
 24	if (not ind) or (ind == "") then ind = ""; sep_n = ", "; _n = "" end
 25	if not pre then pre = "" end
 26	outf ("{")
 27	local p = pre..ind
 28	-- prepare list of keys
 29	local keys = { boolean = {}, number = {}, string = {} }
 30	local total = 0
 31	for key in pairs (tab) do
 32		total = total + 1
 33		local t = type(key)
 34		if t == "string" then
 35			tinsert (keys.string, key)
 36		else
 37			keys[t][key] = true
 38		end
 39	end
 40	local many = total > 5
 41	if not many then sep_n = sep; _n = " " end
 42	outf (_n)
 43	-- serialize entries with numeric keys
 44	if many then
 45		local _f,_s,_v = ipairs(tab)
 46		if _f(_s,_v) then outf (p) end
 47	end
 48	local num = keys.number
 49	local ok = false
 50	-- entries with automatic index
 51	for key, val in ipairs (tab) do
 52		value (val, outf, ind, p)
 53		outf (sep)
 54		num[key] = nil
 55		ok = true
 56	end
 57	if ok and many then outf (_n) end
 58	-- entries with explicit index
 59	for key in pairs (num) do
 60		if many then outf (p) end
 61		outf ("[")
 62		outf (key)
 63		outf ("] = ")
 64		value (tab[key], outf, ind, p)
 65		outf (sep_n)
 66	end
 67	-- serialize entries with boolean keys
 68	local tr = keys.boolean[true]
 69	if tr then
 70		outf (format ("%s[true] = ", many and p or ''))
 71		value (tab[true], outf, ind, p)
 72		outf (sep_n)
 73	end
 74	local fa = keys.boolean[false]
 75	if fa then
 76		outf (format ("%s[false] = ", many and p or ''))
 77		value (tab[false], outf, ind, p)
 78		outf (sep_n)
 79	end
 80	-- serialize entries with string keys
 81	sort (keys.string)
 82	for _, key in ipairs (keys.string) do
 83		outf (format ("%s[%q] = ", many and p or '', key))
 84		value (tab[key], outf, ind, p)
 85		outf (sep_n)
 86	end
 87	if many then outf (pre) end
 88	outf ("}")
 89end
 90
 91
 92--
 93-- Serializes a value.
 94--
 95value = function (v, outf, ind, pre)
 96	local t = type (v)
 97	if t == "string" then
 98		outf (format ("%q", v))
 99	elseif t == "number" then
100		outf (tostring(v))
101	elseif t == "boolean" then
102		outf (tostring(v))
103	elseif t == "table" then
104		tabledump (v, outf, ind, pre)
105	else
106		outf (format ("%q", tostring(v)))
107	end
108end
109
110----------------------------------------------------------------------------
111serialize = tabledump
112
113return tabledump