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.
    Source code comments may be thin at some points because they are intended to be supplemented by the documentation page:
    Licensed under Creative Commons Attribution-ShareAlike 3.0 Unported License
    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
    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
    	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
    			if #ti~=n then
    				for k = 1, #ti do tn[ti[k]] = k + 1 end--somewhat wasteful, but trying to avoid overwriting can be even more expensive
    			for k = 1, #to do tn[to[k]] = k + 1 end
    		return iter and pIter or oMap[t] and pOther or noOp, t--noOp for mapless
    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
    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
    				return self
    			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))
    		function _stream(self, ...) self.last_concat = init() return setmetatable(self, stream):each(...) 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
    	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
    		return ..., seps
    	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
    					return tag
    				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
    			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
    				setmetatable(nonSelf, g)
    				setmetatable(BHi, g)
    			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
    			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)
    				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))
    						return parent[HTML]:_(joinNode(HTML, ...))
    					_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))
    						return joinNode(HTML, ...)
    					_parent = function(HTML, ...) table.insert(HTML.nodes, parent[HTML:allDone()]:_str(...)) return HTML end
    				} do BHi[k] = v 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
    					}, {__index = function(nodes, i)
    						if rawget(BHi, i) then out = BHi[i] return func end--rawget to exclude globals
    				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)
    										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
    								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
    						return nodes
    				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
    			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
    				return lastHTML
    			function MBi:_html(...) return MBi._(self, lastHTML, select(spec[self]==Element and select('#', ...)==0 and 1 or 2, true, ...)) end
    			return init(...)
    		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
    	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
    			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
    			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(...)
    		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
    		function _var(self, ...)
    			local obj if ... and ...~=true then obj = init(...)
    			elseif prev then
    				if ...~=false then obj = rebuild(...)
    				else rebuild(...) end
    			return obj and MBi._(self, obj, nil, true) or self
    	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
    		_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
    					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
    					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
    				self.last_concat = nil
    			return self
    		_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
    			return self
    		_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)
    			return MB.__call(t, ...)
    		_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
    		_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		
    						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
    					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]
    			return self and rawset(self, 'last_concat', nil) or clear
    		_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
    			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]
    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, 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)
    				if rawsep and not raw.s then raw[#raw] = unbuild(sep) end--unbuild rawsep if final index in t was invalid
    				t.last_concat = return table.concat(raw)
    			return table.concat(t, sep, i and math.max(i, 1), j and math.min(j, #t))
    		return MB.__tostring(t)
    	__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
    	__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
    		return table.concat(MBmix(MBmix({}, a), b))
    	__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()return''end,
    	__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
    					return self, ...--avoiding __eq with rawequal(self,save) is overkill since buffers can self-save without being passed as save
    				_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
    				_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
    				_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 ('#', ...)~=1 and G.rawset(k, ...) or G:rawset(..., k) and k) or G:rawset(k, (...)) and ... 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
    	__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