The following little snippet allows you to ‘pickle’ Lua objects directly into Lua code (with the exception of functions, which are serialized as raw bytecode). Metatable support is on the way, but for now, it should be useful enough.
Example code:
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dofile "pickle.lua"
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users = {
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user1 = {pass = "abcdef", start = 10230},
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user2 = {pass = "cdefba", start = 12032}
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}
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userdump = pickle.dumps(users)
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print(userdump)
Outputs
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return {
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["user1"] = {
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["pass"] = "abcdef",
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["start"] = 10230,
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},
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["user2"] = {
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["pass"] = "cdefba",
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["start"] = 12032,
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},
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}
Pickle API:
- pickle.dumps(object) -> String
Pickles an object and returns it.
- pickle.dump(object, filename) -> String
Pickles an object and saves it as :filename, afterwards, returns the dump.
- pickle.loads(object) -> Lua Object
Loads a string dump of lua object and returns the object. The returned object will not injected into the global table.
- pickle.load(filename) -> Lua Object
Loads a pickled object from a file and returns it. The returned object will not be injected into the global table.
Full Source:
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local objects = {}
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setmetatable(objects, {__index={["subset"]=function(object, proxies)
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for _,o in ipairs(proxies) do
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if object == o then return true end
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end
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end}})
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function _pickle(object, seen, indent)
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---if not seen then seen = {} end
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if not indent then indent = "" end
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local serialize_key = function(key)
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if type(key) == "string" then
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return "[\""..key.."\"]"
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elseif type(key) == "table" then
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return "[".._pickle(key):gsub("\n"," ").."]"
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else
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return "["..key.."]"
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end
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return key
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end
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local escape = function(o)
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return o:gsub("\\","\\\\"):gsub("'","\\'"):gsub('"','\\"')
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end
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---Switch Object type:
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if type(object) == "table" then
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local serialize = "{\n"
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for key, value in pairs(object) do
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serialize = serialize .. indent.."\t" .. serialize_key(key) .. " = " ..tostring(_pickle(value, seen, indent.."\t")) .. ",\n"
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end
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serialize = serialize .. indent .. "}"
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return serialize
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elseif type(object) == "string" then
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return '"' .. escape(object) .. '"'
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elseif type(object) == "function" then
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return "loadstring([["..string.dump(object).."]])"
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elseif objects.subset(object, {"userdata"}) then
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return nil
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end
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return tostring(object)
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end
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pickle = {}
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function pickle.dumps(object)
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return "return ".. _pickle(object)
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end
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function pickle.dump(object, filename)
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local dump = pickle.dumps(object)
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local _file = io.open(filename, "wb")
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_file:write(dump)
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_file:close()
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return dump
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end
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function pickle.loads(object)
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local fn = loadstring(object)
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if fn then
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return fn()
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end
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end
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function pickle.load(filename)
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local _file = io.open(filename, "rb")
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local dump = _file:read("*all")
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local object = pickle.loads(dump)
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_file:close()
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return object
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end
