Module:Util/SerLua

-- copied from https://github.com/gvx/Ser -- see license at /license

local pairs, ipairs, tostring, type, concat, dump, floor, format = pairs, ipairs, tostring, type, table.concat, string.dump, math.floor, string.format

local function getchr(c) return "\\" .. c:byte end

local function make_safe(text) return ("%q"):format(text):gsub('\n', 'n'):gsub("[\128-\255]", getchr) end

local oddvals = {[tostring(1/0)] = '1/0', [tostring(-1/0)] = '-1/0', [tostring(-(0/0))] = '-(0/0)', [tostring(0/0)] = '0/0'} local function write(t, memo, rev_memo) local ty = type(t) if ty == 'number' then t = format("%.17g", t)		return oddvals[t] or t	elseif ty == 'boolean' or ty == 'nil' then return tostring(t) elseif ty == 'string' then return make_safe(t) elseif ty == 'table' or ty == 'function' then if not memo[t] then local index = #rev_memo + 1 memo[t] = index rev_memo[index] = t		end return '_[' .. memo[t] .. ']'	else error("Trying to serialize unsupported type " .. ty) end end

local kw = {['and'] = true, ['break'] = true, ['do'] = true, ['else'] = true, ['elseif'] = true, ['end'] = true, ['false'] = true, ['for'] = true, ['function'] = true, ['goto'] = true, ['if'] = true, ['in'] = true, ['local'] = true, ['nil'] = true, ['not'] = true, ['or'] = true, ['repeat'] = true, ['return'] = true, ['then'] = true, ['true'] = true, ['until'] = true, ['while'] = true} local function write_key_value_pair(k, v, memo, rev_memo, name) if type(k) == 'string' and k:match '^[_%a][_%w]*$' and not kw[k] then return (name and name .. '.' or '') .. k ..'=' .. write(v, memo, rev_memo) else return (name or '') .. '[' .. write(k, memo, rev_memo) .. ']=' .. write(v, memo, rev_memo) end end

-- fun fact: this function is not perfect -- it has a few false positives sometimes -- but no false negatives, so that's good local function is_cyclic(memo, sub, super) local m = memo[sub] local p = memo[super] return m and p and m < p end

local function write_table_ex(t, memo, rev_memo, srefs, name) if type(t) == 'function' then return '_[' .. name .. ']=loadstring' .. make_safe(dump(t)) end local m = {} local mi = 1 for i = 1, #t do -- don't use ipairs here, we need the gaps local v = t[i] if v == t or is_cyclic(memo, v, t) then srefs[#srefs + 1] = {name, i, v}			m[mi] = 'nil' mi = mi + 1 else m[mi] = write(v, memo, rev_memo) mi = mi + 1 end end for k,v in pairs(t) do		if type(k) ~= 'number' or floor(k) ~= k or k #t then if v == t or k == t or is_cyclic(memo, v, t) or is_cyclic(memo, k, t) then srefs[#srefs + 1] = {name, k, v}			else m[mi] = write_key_value_pair(k, v, memo, rev_memo) mi = mi + 1 end end end return '_[' .. name .. ']={' .. concat(m, ',') .. '}' end

return function(t) local memo = {[t] = 0} local rev_memo = {[0] = t}	local srefs = {} local result = {}

-- phase 1: recursively descend the table structure local n = 0 while rev_memo[n] do		result[n + 1] = write_table_ex(rev_memo[n], memo, rev_memo, srefs, n)		n = n + 1 end

-- phase 2: reverse order for i = 1, n*.5 do		local j = n - i + 1 result[i], result[j] = result[j], result[i] end

-- phase 3: add all the tricky cyclic stuff for i, v in ipairs(srefs) do		n = n + 1 result[n] = write_key_value_pair(v[2], v[3], memo, rev_memo, '_[' .. v[1] .. ']') end

-- phase 4: add something about returning the main table if result[n]:sub(1, 5) == '_[0]=' then result[n] = 'return ' .. result[n]:sub(6) else result[n + 1] = 'return _[0]' end

-- phase 5: just concatenate everything result = concat(result, '\n') return n > 1 and 'local _={}\n' .. result or result end