modlib/luon.lua
2021-07-06 21:56:20 +02:00

165 lines
4.7 KiB
Lua

local assert, next, pairs, pcall, error, type, table_insert, table_concat, string_format, setfenv, math_huge, loadfile, loadstring
= assert, next, pairs, pcall, error, type, table.insert, table.concat, string.format, setfenv, math.huge, loadfile, loadstring
local count_values = modlib.table.count_values
-- Build a table with the succeeding character from A-Z
local succ = {}
for char = ("A"):byte(), ("Z"):byte() - 1 do
succ[string.char(char)] = string.char(char + 1)
end
local function quote(string)
return string_format("%q", string)
end
local _ENV = {}
setfenv(1, _ENV)
function serialize(object, write)
local reference = {"A"}
local function increment_reference(place)
if not reference[place] then
reference[place] = "B"
elseif reference[place] == "Z" then
reference[place] = "A"
return increment_reference(place + 1)
else
reference[place] = succ[reference[place]]
end
end
local references = {}
local to_fill = {}
for value, count in pairs(count_values(object)) do
local type_ = type(value)
if count >= 2 and ((type_ == "string" and #reference + 2 >= #value) or type_ == "table") then
local ref = table_concat(reference)
write(ref)
write"="
write(type_ == "table" and "{}" or quote(value))
write";"
references[value] = ref
if type_ == "table" then
to_fill[value] = true
end
increment_reference(1)
end
end
local function is_short_key(key)
return not references[key] and type(key) == "string" and key:match"^[%a_][%a%d_]*$"
end
local function dump(value)
-- Primitive types
if value == nil then
return write"nil"
end
if value == true then
return write"true"
end
if value == false then
return write"false"
end
local type_ = type(value)
if type_ == "number" then
return write(("%.17g"):format(value))
end
-- Reference types: table and string
local ref = references[value]
if ref then
-- Referenced
if not to_fill[value] then
return write(ref)
end
-- Fill table
to_fill[value] = false
for k, v in pairs(value) do
write(ref)
if is_short_key(k) then
write"."
write(k)
else
write"["
dump(k)
write"]"
end
write"="
dump(v)
write";"
end
elseif type_ == "string" then
return write(quote(value))
elseif type_ == "table" then
local first = true
write"{"
local len = #value
for i = 1, len do
if not first then write";" end
dump(value[i])
first = false
end
for k, v in next, value do
if type(k) ~= "number" or k % 1 ~= 0 or k < 1 or k > len then
if not first then write";" end
if is_short_key(k) then
write(k)
else
write"["
dump(k)
write"]"
end
write"="
dump(v)
first = false
end
end
write"}"
else
error("unsupported type: " .. type_)
end
end
local fill_root = to_fill[object]
if fill_root then
-- Root table is circular, must return by named reference
dump(object)
write"return "
write(references[object])
else
-- Root table is not circular, can directly start writing
write"return "
dump(object)
end
end
function serialize_file(object, file)
return serialize(object, function(text)
file:write(text)
end)
end
function serialize_string(object)
local rope = {}
serialize(object, function(text)
table_insert(rope, text)
end)
return table_concat(rope)
end
function deserialize(...)
local read = assert(...)
-- math.huge is serialized to inf, 0/0 is serialized to -nan
setfenv(read, {inf = math_huge, nan = 0/0})
local success, value_or_err = pcall(read)
if success then
return value_or_err
end
return nil, value_or_err
end
function deserialize_file(path)
return deserialize(loadfile(path))
end
function deserialize_string(string)
return deserialize(loadstring(string))
end
return _ENV