Module:Buffer

--[[============================= This Module was written by Alexander Zhikun He, also known as, User:Codehydro on the English Wikipedia

All methods were developed independently and any resemblance to other string buffer libraries would be coincidental. Furthermore, many methods will not work when compiled by standard Lua libraries as they depend on behaviors unique to the MediaMiki Scribunto mod, which, for example, has a getmetatable() method that always returns nil on non-tables. https://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual

Source code comments may be thin at some points because they are intended to be supplemented by the documentation page: https://en.wikipedia.org/wiki/Module:Buffer/doc

Licensed under Creative Commons Attribution-ShareAlike 3.0 Unported License https://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_License

https://en.wikipedia.org/wiki/Module:Buffer https://en.wikipedia.org/wiki/User:Codehydro =============================--]] local function Valid(v)--type validation if v and v~=true then--reject nil/boolean; faster than 2 type() comparisons local str = tostring(v)--functions not filtered since unlikely passed by accident (Scribunto does not have userdata/thread types) if str~=v and str=='table' then return rawget(v, 1) and table.concat(v) end--tostring(string-type) returns same ref; same refs compare faster than type() if str~= then return str end--numbers are coerced to string per table.concat op; appending in string form saves ops on repeat concat end end local noOp, MBpairs = function()end do local iMap, vMap, oMap, pIter, pOther, pFast, Next--Map local function init()--init = noOp after first run function Next(t) return next, t end--slightly faster to do this than to use select() function pIter(t, k) k = (iMap[t] or MBpairs(t, true) and iMap[t])[not k and 1 or vMap[t][k]] return k, t[k] end--don't use rawget; accepting unmapped tables does not measurably affect performance. function pOther(t, k) k = (oMap[t] or MBpairs(t, true) and oMap[t])[nil==k and 1 or vMap[t][k]] return k, t[k] end--comparison to nil because false is a valid key function pFast(t, k) k = not k and 1 or k < (vMap[t] or #t) and k + 1 or nil return k, t[k] end--mapless iterator; almost as fast as native ipairs; slight performance penalty when length not cached --k and k < (vMap[t] or #t) and k + 1 or not k and 1 or nil return k, t[k] end--mapless iterator; almost as fast as native ipairs; slight performance penalty when length not cached local mk = {__mode = 'k'}--use mode 'k'; found that mode 'kv' sometimes garbage collects maps mid-loop (may not error because iterators auto re-map, but that's expensive) init, iMap, vMap, oMap = noOp, setmetatable({}, mk), setmetatable({}, mk), setmetatable({}, mk)--iMap is numeric keys, oMap is non-numeric keys, and vMap points to next key end function MBpairs(t, ...)--pairs always iterates in order local iter, ex = ... iter = iter==init()--nil if iter and not oMap[t] and ex==nil and rawget(t, 1)~=nil and next(t, #t)==nil then--while possible to miss keys, more thorough check would negate the benefit of pFast vMap[t] = #t return pFast, t, nil elseif ... or not vMap[t] or select('#', ...)~=1 then local ti, tn, to, n = {}, {}, {}, #t--reduces table lookups iMap[t], vMap[t], oMap[t] = ti, tn, to for k = 1, n do ti[k], tn[k] = k, k + 1 end--stage one avoids number type checking op in stage two for most numeric keys for k in (ex or Next)(t) do if not tn[k] then table.insert(tonumber(k)~=k and to or ti, k) end end if #ti~=n then table.sort(ti) for k = 1, #ti do tn[ti[k]] = k + 1 end--somewhat wasteful, but trying to avoid overwriting can be even more expensive end for k = 1, #to do tn[to[k]] = k + 1 end end return iter and pIter or oMap[t] and pOther or noOp, t--noOp for mapless end end local parent, rawkey, spec do--new scope for variables not reused outside (reduces number of var names that need to checked outside of scope) local mkv = {__mode='kv', __call=function(t,k,v)t[k]=v return k end}--shared meta for Buffer parent property, raw mode, and specialized functions parent, rawkey, spec = setmetatable({}, mkv), setmetatable({}, mkv), setmetatable({}, mkv)--shared meta less memory end

local MB, MBi, MBmix, buffHTML, gfuncs, noCache, Element do--minimize number of locals per scope to reduce time spent sifting through irrelevant variable names local _stream do local stream--keep stream near top of scope local function init(f)--init = noOp after first run local function each(self, ...) for k = 1, select('#', ...) do k = Valid(select(k, ...))--slightly faster than table.insert(self, (Valid(select(k, ...)))) if k then table.insert(self, k) end end return self end init, stream, _stream = noOp, { __call = function(t, v) v = v and Valid(v) return v and table.insert(t, v) or t end,--last_concat cleared before entering stream mode __index = function(t, i) return i=='each' and each or MB.__index(t, i) and setmetatable(t, MB)[i] end,--no table look up minimizes resources to retrieve the only stream function __tostring = function(t) return setmetatable(t, MB)() end } for k, v in next, MB do stream[k] = stream[k] or v end setmetatable(stream, getmetatable(MB)) end function _stream(self, ...) self.last_concat = init() return setmetatable(self, stream):each(...) end end local function isMBfunc(Buffer, s, ...)--helper for :getParent()-like methods (including getBuffer which does not return a parent) return s and (select('#', ...)==0 and--eventually should figure out to make this work for :getHTML which is very similar (not rawkey[s] and tostring(s):match'^_.*' and MB.__index(Buffer, s) and MB.__index(Buffer, s)(Buffer) or MBmix(Buffer, s))--unprefixed function names append as a string or assert(MB.__index(Buffer, s), ('" %s " does not match any available Module:Buffer function'):format(s))(Buffer, ...)--getParent is a one-way trip so one-time assert not expensive ) or Buffer end local function MBselect(n, ...)--helper for :_out and :_str local n, seps = n - 1, {select(2, ...)} if type(seps[n])=='table' then if buffHTML and rawget(seps[n], buffHTML) then return ... end setmetatable(seps, {__index = setmetatable(seps[n], {__index = function(t) return rawget(t, 1) end})})[n] = nil end return ..., seps end local _inHTML do local lastBuffer, lastHTML local function init(...)--init replaced and new version called on return local create, mwFunc = mw.html.create do local mwHTMLmeta = getmetatable(create()) buffHTML, mwFunc, _inHTML = setmetatable(mw.clone(mwHTMLmeta), getmetatable(MB)), mwHTMLmeta.__index--buffHTML declared near top of module; remove _inHTML from outer scope function init(nodes, ...) local name, args, tag = select(... and type(...)=='table' and 1 or 2, nil, ...) tag = create(Valid(name), args) if nodes then table.insert(nodes, tag.parent and tag or rawset(tag, 'parent', parent[nodes])) end if args then local a, b = args.selfClosing, args.parent args.selfClosing, args.parent = nil if next(args) then Element._add(parent(tag.nodes, tag), args) end args.selfClosing, args.parent = a, b--in case args is reused end return tag end for k, v in next, {[mw] = mwHTMLmeta, __call = function(h, v) return MBmix(spec[h.nodes] and h.nodes or spec(setmetatable(parent(h.nodes, h), MB), Element), v) end, __concat = false,--false means take from MB __eq = false } do buffHTML[k] = v or MB[k] end end local nonSelf, BHi = {tag=true,done=true,allDone=true}, buffHTML.__index do local g g = {__index = function(t, i) if gfuncs and gfuncs[i] then g.__index, gfuncs = gfuncs return g.__index[i] end end} setmetatable(nonSelf, g) setmetatable(BHi, g) end for k in next, nonSelf do--any HTML objects returned by these funcs will be granted Module:Buffer enhancements local func = mwFunc[k] BHi[k] = function(t, ...) local HTML = func(t, ...) return parent[HTML] and HTML or setmetatable(parent(HTML, t), buffHTML) end end do local function joinNode(HTML, sep) local nodes, join = HTML.nodes if noCache and rawkey[sep] or Valid(sep) then join, HTML.nodes = tostring(rawset(HTML, 'nodes', {MB.__call(nodes, sep)})), nodes end return join or tostring(HTML) end for k, v in next, { getParent = function(HTML, ...) lastHTML = HTML return MBi.getParent(HTML:allDone(), ...) end,--return to Buffer that created the HTML tree getBuffer = function(HTML, ...) lastHTML = HTML return isMBfunc(lastBuffer, ...) end,--return to last used killParent = function(HTML, ...) MBi.killParent(HTML:allDone(), ...) return HTML end, _out = function(HTML, ...) if ...==0 then MBi._out(HTML.nodes, ...) return HTML end lastHTML, HTML = HTML, HTML:allDone() local n, ops, seps = select('#', ...) if n > 1 then local ops, seps = MBselect(n, ...) return parent[HTML]:_in(joinNode(HTML, rawget(seps, 0))):_out(ops, rawset(seps, buffHTML, true)) end return parent[HTML]:_(joinNode(HTML, ...)) end, _str = function(HTML, ...)--does not set lastHTML if ...==0 then return joinNode(HTML, select(2, ...)) end--passing 0 strings without calling allDone() local HTML, n = HTML:allDone(), select('#', ...) if n > 1 then local ops, seps = MBselect(n, ...) return parent[HTML]:_in(joinNode(HTML, rawget(seps, 1))):_str(ops, rawset(seps, buffHTML, true)) end return joinNode(HTML, ...) end, _parent = function(HTML, ...) table.insert(HTML.nodes, parent[HTML:allDone()]:_str(...)) return HTML end } do BHi[k] = v end end do local htmlArg, skip, outFuncs = {parent=true,selfClosing=true,tagName=true}, {} do local out local function func(nodes, ...) return out(parent[nodes], ...) end outFuncs = setmetatable({ tag = function(nodes, ...) return parent(setmetatable(init(nodes, ...), buffHTML), parent[nodes]) end, done = function(b, ops) b = parent[b] while b.parent and ops~=0 do b, ops = b.parent, ops and ops - 1 or 0 end return b end }, {__index = function(nodes, i) if rawget(BHi, i) then out = BHi[i] return func end--rawget to exclude globals end}) end Element = { _add = function(nodes, t) for k, v in MBpairs(t), t, skip[t] do (v~=true and MBmix or noOp)(nodes, v) end local HTML = parent[nodes] for k, v in MBpairs(t, false) do if htmlArg[k] then HTML[k] = v elseif v and v~=true then if nonSelf[k] then if k=='tag' then if type(v)=='table' then skip[v], k = 1, rawset(create(Valid(v[1])), 'parent', HTML) Element._add(spec(parent(k.nodes, k, table.insert(nodes, k)), Element), v) if k.selfClosing then k.nodes = nil else spec[k.nodes], parent[k.nodes] = nil end--free memory/reduce clutter; parent ref will auto-unset when k.nodes is nil if not k.tagName then k.styles, k.attributes = nil end else table.insert(nodes, create(v)) end elseif mwFunc[k] then if k=='done' and tonumber(v)~=v and v[1] and tonumber(v[1])==v[1] then skip[v] = 1 end MBmix(outFuncs[k](nodes, skip[v] and v[1]).nodes, v) elseif v[1] or v[2] then k = MBi[k](nodes, unpack(v, 1, rawset(skip, v, k=='_B' and 1 or 2)[v])) Element._add(getmetatable(k) and rawget(k, 'nodes') or k, v)--if k is not a table, then v should not contain any extra keys or this may error. else MBi[k](nodes, v) end--k probably == '_G' or '_R' elseif mwFunc[k] then if type(v)~='table' or rawget(v, 'nodes') then mwFunc[k](HTML, v) else local css = k=='css' for x, y in MBpairs(v, true) do (y and y~=true and mwFunc[k] or noOp)(HTML, css and x:gsub('_', '-') or x, y) end--iterate non-numbers first for _, y in MBpairs(v, nil) do (y and y~=true and mwFunc[k] or noOp)(HTML, y) end--don't bother with gsub since text must be quoted anyhow end elseif rawget(Element, k) or rawget(MBi, k) then if tonumber(v)==v or v[1]==nil or getmetatable(v) then (Element[k] or MBi[k])(nodes, v)--v is probably string-able object, or a table to be handled by :_all else (Element[k] or MBi[k])(nodes, unpack(v, 1, table.maxn(v))) end--v is definately a table else mwFunc.css(HTML, k:gsub('_', '-', 1), tostring(v)) end--oddly enough, :_add clocked its fastest runtime after adding auto-gsub as a feature skip[v] = nil end end return nodes end } local tempMeta = {mode='v', copy={styles=true,attributes=true}} function tempMeta.__index(t, i) return tempMeta.copy[i] and rawset(t, i, MBi._cc(false, 0, t.orig[i]))[i] or t.orig[i] end rawkey[setmetatable(Element, {__index = outFuncs, __concat=function(Element, v) return setmetatable({nodes=spec({}, Element),orig=parent[v]}, tempMeta) end})] = math.huge end function MBi:getHTML(...) lastBuffer = self if ... then if select('#', ...)==1 then return not rawkey[s] and tostring(...):match'^_' and BHi[...] and BHi[...](lastHTML) or lastHTML(...) else return assert(BHi[...], ('" %s " does not match any mw.html or Buffer-mw.html function'):format(tostring(...)))(lastHTML, select(2, ...)) end end return lastHTML end function MBi:_html(...) return MBi._(self, lastHTML, select(spec[self]==Element and select('#', ...)==0 and 1 or 2, true, ...)) end return init(...) end function _inHTML(self, ...) local HTML = init(nil, ...) if HTML.selfClosing and spec[self]==Element then self.last_concat = table.insert(self, HTML) return self end lastBuffer, lastHTML = self, setmetatable(parent(HTML, self), buffHTML)--set after 'args' table processed by :_add return HTML end end local _var, unbuild do local prev, rebuild local function init(...)--init replaced before return local function pick(b, v) return b and table.insert(b, v) or v end local function c(a, num) return rawset(a.a or a, 0, a[0] and a[0] + a.c or num and a[1] or a[1]:byte())[0] end local same, build, alt = {__tostring = function(a, b) return a.a[0] and pick(b, a.a.string and string.char(a.a[0]) or a.a.table and a.a[1][a.a[0]] or a.a[0]) end}, { __index = {c = 1}, __tostring = function(t) return t:_build() end, table = function(a, b) local i = next(a[1], a[0]) or a[0]==#a[1] and next(a[1]) return pick(b, rawset(a.a or a, 0, i)[1][i]) end,--change rate (a.c) ignored since users control the table's contents number = function(a, b) return pick(b, c(a, true)) end, string = function(a, b) return pick(b, string.char(c(a))) end }, {__index = function(a, i) return a.a[i] end, __tostring = function(a, b) return (rawget(a, 0) and a[0]==tostring(a[0]) and rawset(a, 0, a[0]:byte()) or a).a._build(a, b) end} local function shift(t, c) t[0] = t[0] and t[0] + c or t:_build() and t[0] - t.c + c if t.table then t[0] = (t[0] - 1) % #t[1] + 1 end end function rebuild(...) local v, c = ... if v or select('#', ...)==0 then if v and not c then return prev end local meta, c = select(v and 1 or 3, alt, c, same, 0) return setmetatable({a = prev, _build = meta.__tostring, c = c}, meta) elseif v==nil then--no-op elseif c then shift(prev, c)--v == false else prev:_build() end end init, noCache = function(v, c) prev = setmetatable({v, c = c, _build = build[type(v)] or v, [type(v)] = true, alt = {}}, build) return prev end, true return init(...) end function unbuild(sep) for k, v in MBpairs(sep, nil) do k = getmetatable(v) if k and (k==build or k==alt) then shift(v.a or v, -v.c) end end end function _var(self, ...) local obj if ... and ...~=true then obj = init(...) elseif prev then if ...~=false then obj = rebuild(...) else rebuild(...) end end return obj and MBi._(self, obj, nil, true) or self end end local lib; MBi = setmetatable({stream = _stream, _inHTML = _inHTML, _var = _var, _ = function(self, v, ...) local at, raw = select(select('#', ...)==1 and ...==true and 1 or 2, nil, ...) if raw then rawkey[self] = math.huge else v = Valid(v) end if v or raw then if at or rawkey[self] then raw = #self end--if length increases by more than one after table.insert, then set rawkey[self] = math.huge; rawkey[self] may be equal to a previous 'at' at, self.last_concat = at and (tonumber(at)~=at and raw + at or at) table.insert(self, select(at and 1 or 2, at, v)) if at and at < 0 or raw and #self - raw > 1 then rawkey[self] = math.huge elseif at and #self==raw then rawkey[self] = rawkey[self] and math.max(rawkey[self], at) or at end end--above line looks bizarre because one table.insert op may make length jump from 0 to 8: local wtf={[2]=2,[4]=4,[8]=8}mw.log(#wtf,table.insert(wtf,1),#wtf) return self end, _nil = function(self, at, ...) if ...~=true and ...~=false then--faster than type(...) ~= 'boolean' if not at or at=='0' then self[#self] = ... if ... then rawkey[self] = math.huge end else local n, v = tonumber(at), ... if n~=at then if n then n = #self + at elseif at~=true and select('#', ...)==0 then v, n = at, #self end end if n then if v==nil and n > 0 then table.remove(self, n) else self[math.floor(n)], rawkey[self] = v, math.huge end--floor position for consistency with Table library end end self.last_concat = nil end return self end, _all = function(self, t, valKey) for k, v in MBpairs(t) do MBmix(self, v, valKey) end for k, v in valKey and MBpairs(t, false) or noOp, t do if tonumber(v) then MBi._(self, k, v)--self not always a buffer elseif rawget(MBi, k) and v and v~=true then if v[1]==nil or getmetatable(v) then MBi[k](self, v) else MBi[k](self, unpack(v, 1, table.maxn(v))) end end end return self end, _str = function(t, ...) local n = select('#', ...) if n > 1 then local k, ops, seps, r = 2, MBselect(n, ...) r = MB(t(seps[1])) while parent[t] and ops > 1 and r:_(parent[t](seps[k]), 1) do t, k, ops = parent[t], k + 1, ops - 1 end return table.concat(r, seps[k] or nil) end return MB.__call(t, ...) end, _in = function (self, ...) return parent(MB(...), self) end, _out = function(t, ...) if ...==0 then return parent(t, parent[t], MBi._cc(t, t, MB.__call(t, (select(2, ...))), getmetatable(t))) end--love how :_cc needed nothing new to implement this *self pat on back* local n = select('#', ...) if n > 1 then local k, ops, seps = 1, MBselect(n, ...) while parent[t] and ops > 0 do t, k, ops = parent[t]:_(t(seps[k])), k + 1, ops - 1 end elseif parent[t] then return parent[t]:_(t(...)) end return t end, _cc = function(self, clear, copy, meta) if clear then if rawequal(clear, copy) then return self, spec[MBi._cc] and setmetatable(spec[MBi._cc], MB)--rawequal to avoid re-string via __eq in case both are different Buffer objects elseif copy==true then copy = self end if clear~=0 then assert(type(clear)=='table', debug.traceback('Buffer:_cc can only "clear" tables. Did you forget to call with a colon?', 2))--errors can be hard to trace without this for k in self and next or noOp, clear do rawset(clear, k, nil) end else return MBi._cc(false, {unpack(copy)}, copy) end--copy length w/o empty strings; recursion to avoid self = false causing garbage collection (non-weak child may exist) if self==false or copy and type(copy)=='table' then--self==false means copy is a table (saves a type op for recursive calls) meta = meta or getmetatable(copy) if self and #copy > 1 then--preserves length with empty strings; developed from studying http://www.lua.org/source/5.1/ltable.c.html local n, null, i, e = #copy, {}, math.ldexp(2, select(2, math.frexp(#copy)) - 2) e, spec[MBi._cc], parent[null] = i - 1, null, clear for k = 1, e do table.insert(clear, false) end while i<=n do table.insert(clear, i, ) i, null[i] = i + math.ldexp(2, select(2, math.frexp(n - i)) - 2), end for k = 1, e do rawset(clear, k, nil) end end for k, v in next, copy do rawset(clear, k, type(v)=='table' and MBi._cc(false, 0, v) or v) end elseif copy then rawset(clear, 1, (Valid(copy))) end rawkey[setmetatable(clear, meta)], parent[clear] = rawkey[copy], parent[copy] end return self and rawset(self, 'last_concat', nil) or clear end, _parent = function(self, ...) return parent[self] and MBi._(self, parent[self]:_str(...)) or self end, getParent = function(self, ...) return isMBfunc(parent[self] or parent[parent(self, setmetatable({}, MB))], ...) end, killParent = function(self, ...) return parent[self] and isMBfunc(parent[self], ...) and parent(self) or self end, _build = function(self, t) table.insert(t, self()) end,--for compatibility with mw.html:node() last_concat = false--prevent library check }, {__index = function(t, i)--import string, mw.text, and mw.ustring libraries on an as-needed basis local func = string[i] or mw.text[i] or mw.ustring[i] or type(i)=='string' and mw.ustring[i:match'^u(.+)'] if func then lib = lib or function (s, f, ...) if parent[s] and next(s)==nil then return s:_((f(tostring(parent[Element and (spec[s]==Element and s:allDone() or spec[parent[s]]==Element and parent[s]) or s]), ...))) end return f(tostring(s), ...)--not using ternary/logical operators here to allow multiple return values end return rawset(t, i, i:match'^u?gsub' and function(self, p, r, ...)return lib(self, func, p, r or , ...)end--Why are ugsub/gsub special? because empty strings are against my religion! or function(self, ...)return lib(self, func, ...)end)[i] end end}) end

function MBmix(t, v, ...) return v and ((type(v)~='table' or getmetatable(v)) and MBi._(t, v) or (select('#', ...)==0 and spec[t] and spec[t]._add or MBi._all)(t, v, ...)) or t end--:_all always passes two args

local _G, new_G = _G--localize _G for console testing (console _G ~= module _G) return setmetatable({__index = function(t, i) return spec[t] and spec[t][i] or MBi[i] end, __call = function(t, ...) local rawsep, sep, i, j, raw = noCache and rawkey[...] and ..., ... if i or j or rawsep or Valid(sep) then raw, sep, i, j = rawkey[spec[t]] or rawkey[t], rawsep or Valid(sep), i and (i~=tonumber(i) and i + #t or i), j and (j~=tonumber(j) and j + #t or j) if rawsep or raw and (raw>=(j or #t) or i < 1) then raw, i, j = {}, i and math.floor(i), j and math.floor(j)--floor for consistency with table.concat(t, sep, i, j), which ignores decimals raw.lc, t.last_concat = t.last_concat--temporarily unset last_concat to prevent disqualification from mapless iteration for k, v in MBpairs(t) do if raw[1] or not i or k>=i then if j and k > j then break end if raw.s then raw.s = table.insert(raw, tostring(sep)) end--if sep contains v and v is a Buffer-variable, sep must be strung before v k = Valid(v) if k then raw.s = rawsep or sep and raw[1] and table.insert(raw, sep) table.insert(raw, k) end end end if rawsep and not raw.s then raw[#raw] = unbuild(sep) end--unbuild rawsep if final index in t was invalid t.last_concat = raw.lc return table.concat(raw) end return table.concat(t, sep, i and math.max(i, 1), j and math.min(j, #t)) end return MB.__tostring(t) end, __tostring = function(t) if t.last_concat then return t.last_concat end local r = rawkey[spec[t]] or rawkey[t] r = table.concat(r and r>=#t and MBi._all({}, t) or t) return (noCache or rawset(t, 'last_concat', r)) and r end, __concat = function(a, b) if buffHTML then for k = 1, 2 do local v = select(k, a, b)--faster than for k, v in pairs{a, b} do if v and spec[v] and spec[v]==Element then if parent[v].selfClosing then if rawequal(a, b) then return (not noCache or parent[v].tagName) and v:_str(0):rep(2) or v:_str(0)..v:_str(0) end--rawequal avoids premature tostring of Buffer:_var objects; b, a = select(k, b, parent[v], a) else local temp = Element .. v --helper method; returns a mirror of parent[v] MBmix(MBmix(parent(temp.nodes, temp), a), k==1 and spec[b]==Element and parent[b] or b) return buffHTML.__tostring(setmetatable(temp, {__index=parent[v], __mode='v'}))--switch from tempMeta to avoid MBi._cc op of styles/attributes end end end end return table.concat(MBmix(MBmix({}, a), b)) end, __pairs = MBpairs, __ipairs = MBpairs, __eq = function(a, b) return tostring(a)==tostring(b) end--avoid a==b in this module; use rawequal(a,b) when they may be different Buffers (premature tostring waste ops and is bad for Buffer:_var) }, {__tostring = function()returnend, __call = function(self, ...) MB = MB or self if new_G then if ... and _G and ...==_G then new_G = ... end elseif ... and (...==_G or type(...)=='table' and (...)._G==...) then local Nil, mG = {}, (...):getmetatable() or (...):setmetatable{}:getmetatable() new_G, _G, gfuncs = ..., ..., {--gfuncs stored for Buffer:_inHTML; new_G is a is a Module:Buffer local declared just before the final return statement. _G = function(self, i, ...) local X, save = rawget(new_G, i), select('#', ...)==0 and self or ... if i and i~=true and not (X and save and rawequal(X, save)) and rawset(new_G, i, save) and (X~=nil or save==nil and new_G[i]~=nil) then--rawequal in case X is another buffer local mG = getmetatable(new_G) or {__call=mG.__call} if mG.__index then pcall(rawset, mG.__index, i, X) else mG.__index = setmetatable(new_G, mG) and {[i] = X} end end return self, ...--avoiding __eq with rawequal(self,save) is overkill since buffers can self-save without being passed as save end, _R = function(self, i, v, m) if i~='new_G' then if i and i~=true then rawset(new_G, i , v) end elseif not v or v==true or v._G~=_G then new_G = setmetatable(v~=true and v or {}, {__call = mG.__call, __index = v~=true and m~=true and (m or new_G) or nil}) else new_G, (not m and (m~=nil or v==new_G) and Nil or getmetatable(v)).__index = v, m~=true and (m or new_G) or nil end--setting Nil.__index is noOp return self end, _2 = function(self, ...) if new_G[...]~=nil then return new_G[...] end--higher priority so Buffer:_G('new_G', ...) can prevent an overwrite if ...=='new_G' then return rawset((select('#', ...)~=1 and MBi._R(new_G, ...) or new_G), '_G', _G) end return select(select('#', ...)==1 and 1 or 2, self:_G(...))--return only one value; 'return select(2, self:_G(...)) or self' doesn't work for returning nil end, _B = function(self, v) return v or v==nil and Nil end } for k, v in next, gfuncs do MBi[k] = v end setmetatable(Nil,{__concat=MB.__concat,__newindex=noOp,__call=noOp,__tostring=noOp,__metatable=MB,__index=setmetatable({_B=MBi._B,_=function()return Nil end,last_concat=}, {__index=function(t,i)return (MBi[i] or i and not tonumber(i)) and t._ or nil end})}) function mG.__call(G, k, ...) return (k._G or G.type(k)=='table') and (G.select('#', ...)~=1 and G.rawset(k, ...) or G:rawset(..., k) and k) or G:rawset(k, (...)) and ... end end local new = setmetatable({}, self) if ... and (...)==new_G then return select(2, ...) and MBmix(new:_G((select(2, ...))), select(3, ...)) or new end return ... and MBi._(new, ...) or new end, __index = function(t, i) MB = MB or t return MBi[i] and function(...) return MBi[i](setmetatable({}, t), select(...==t and 2 or 1,...)) end end })