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This is an old revision of this page, as edited by Aidan9382 (talk | contribs) at 11:40, 12 May 2023 (allow call mt). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

--[[
This module is designed to perform analysis on other modules, and is to be
invoked via the Debug console. The majority of the code here is copied from a
seperate project, https://github.com/9382/Dump/tree/main/LuaObfusactor, which in
turn has code borrowed from https://github.com/stravant/LuaMinify.
--]]

require("strict")
local print = mw and mw.log or print

local function lookupify(tb)
	for _, v in pairs(tb) do
		tb[v] = true
	end
	return tb
end

local WhiteChars = lookupify{' ', '\n', '\t', '\r'}
local LowerChars = lookupify{'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 
							 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 
							 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'}
local UpperChars = lookupify{'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 
							 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 
							 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'}
local Digits = lookupify{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'}
local HexDigits = lookupify{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 
														'A', 'a', 'B', 'b', 'C', 'c', 'D', 'd', 'E', 'e', 'F', 'f'}

local Symbols = lookupify{'+', '-', '*', '/', '^', '%', ',', '{', '}', '[', ']', '(', ')', ';', '#'}

local Keywords = lookupify{
		'and', 'break', 'do', 'else', 'elseif',
		'end', 'false', 'for', 'function', 'goto', 'if',
		'in', 'local', 'nil', 'not', 'or', 'repeat',
		'return', 'then', 'true', 'until', 'while',
};

local BackslashEscaping = {
	a="\a", b="\b", f="\f", n="\n", r="\r", t="\t", v="\v",
	["\\"]="\\", ['"']='"', ["'"]="'", ["["]="[", ["]"]="]"
}

local function LexLua(src)
	--token dump
	local tokens = {}

	local st, err = pcall(function()
		--line / char / pointer tracking
		local p = 1
		local line = 1
		local char = 1

		--get / peek functions
		local function get()
			local c = src:sub(p,p)
			if c == '\n' then
				char = 1
				line = line + 1
			else
				char = char + 1
			end
			p = p + 1
			return c
		end
		local function peek(n)
			n = n or 0
			return src:sub(p+n,p+n)
		end
		local function consume(chars)
			local c = peek()
			for i = 1, #chars do
				if c == chars:sub(i,i) then return get() end
			end
		end

		--shared stuff
		local function generateError(err)
			return error(">> :"..line..":"..char..": "..err, 0)
		end

		local function tryGetLongString()
			local start = p
			if peek() == '[' then
				local equalsCount = 0
				while peek(equalsCount+1) == '=' do
					equalsCount = equalsCount + 1
				end
				if peek(equalsCount+1) == '[' then
					--start parsing the string. Strip the starting bit
					for _ = 0, equalsCount+1 do get() end

					--get the contents
					local contentStart = p
					while true do
						--check for eof
						if peek() == '' then
							generateError("Expected `]"..string.rep('=', equalsCount).."]` near <eof>.", 3)
						end

						--check for the end
						local foundEnd = true
						if peek() == ']' then
							for i = 1, equalsCount do
								if peek(i) ~= '=' then foundEnd = false end
							end 
							if peek(equalsCount+1) ~= ']' then
								foundEnd = false
							end
						else
							foundEnd = false
						end
						--
						if foundEnd then
							break
						else
							get()
						end
					end

					--get the interior string
					local contentString = src:sub(contentStart, p-1)

					--found the end. Get rid of the trailing bit
					for i = 0, equalsCount+1 do get() end

					--get the exterior string
					local longString = src:sub(start, p-1)

					--return the stuff
					return contentString, longString
				else
					return nil
				end
			else
				return nil
			end
		end

		--main token emitting loop
		while true do
			--get leading whitespace. The leading whitespace will include any comments 
			--preceding the token. This prevents the parser needing to deal with comments 
			--separately.
			local leadingWhite = ''
			while true do
				local c = peek()
				if WhiteChars[c] then
					--whitespace
					leadingWhite = leadingWhite..get()
				elseif c == '-' and peek(1) == '-' then
					--comment
					get();get()
					leadingWhite = leadingWhite..'--'
					local _, wholeText = tryGetLongString()
					if wholeText then
						leadingWhite = leadingWhite..wholeText
					else
						while peek() ~= '\n' and peek() ~= '' do
							leadingWhite = leadingWhite..get()
						end
					end
				else
					break
				end
			end

			--get the initial char
			local thisLine = line
			local thisChar = char
			local c = peek()

			--symbol to emit
			local toEmit = nil

			--branch on type
			if c == '' then
				--eof
				toEmit = {Type = 'Eof'}

			elseif UpperChars[c] or LowerChars[c] or c == '_' then
				--ident or keyword
				local start = p
				repeat
					get()
					c = peek()
				until not (UpperChars[c] or LowerChars[c] or Digits[c] or c == '_')
				local dat = src:sub(start, p-1)
				if Keywords[dat] then
					toEmit = {Type = 'Keyword', Data = dat}
				else
					toEmit = {Type = 'Ident', Data = dat}
				end

			elseif Digits[c] or (peek() == '.' and Digits[peek(1)]) then 
				--number const
				local start = p
				if c == '0' and peek(1) == 'x' then
					get();get()
					while HexDigits[peek()] do get() end
					if consume('Pp') then
						consume('+-')
						while Digits[peek()] do get() end
					end
				else
					while Digits[peek()] do get() end
					if consume('.') then
						while Digits[peek()] do get() end
					end
					if consume('Ee') then
						consume('+-')
						while Digits[peek()] do get() end
					end
				end
				toEmit = {Type = 'Number', Data = src:sub(start, p-1)}

			elseif c == '\'' or c == '\"' then
				--string const
				local delim = get()
				local content = ""
				while true do
					local c = get()
					if c == '\\' then
						local next = get()
						local replacement = BackslashEscaping[next]
						if replacement then
							content = content .. replacement
						else
							if next == "x" then
								local n1 = get()
								if n1 == "" or n1 == delim or not Digits[n1] then
									generateError("invalid escape sequence near '"..delim.."'")
								end
								local n2 = get()
								if n2 == "" or n2 == delim or not Digits[n2] then
									generateError("invalid escape sequence near '"..delim.."'")
								end
								content = content .. string.char(tonumber(n1 .. n2, 16))
							elseif Digits[next] then
								local num = next
								while #num < 3 and Digits[peek()] do
									num = num .. get()
								end
								content = content .. string.char(tonumber(num))
							else
								generateError("invalid escape sequence near '"..delim.."'")
							end
						end
					elseif c == delim then
						break
					elseif c == '' then
						generateError("Unfinished string near <eof>")
					else
						content = content .. c
					end
				end
				toEmit = {Type = 'String', Data = delim .. content .. delim, Constant = content}

			elseif c == '[' then
				local content, wholetext = tryGetLongString()
				if wholetext then
					toEmit = {Type = 'String', Data = wholetext, Constant = content}
				else
					get()
					toEmit = {Type = 'Symbol', Data = '['}
				end

			elseif consume('>=<') then
				if consume('=') then
					toEmit = {Type = 'Symbol', Data = c..'='}
				else
					toEmit = {Type = 'Symbol', Data = c}
				end

			elseif consume('~') then
				if consume('=') then
					toEmit = {Type = 'Symbol', Data = '~='}
				else
					generateError("Unexpected symbol `~` in source.", 2)
				end

			elseif consume('.') then
				if consume('.') then
					if consume('.') then
						toEmit = {Type = 'Symbol', Data = '...'}
					else
						toEmit = {Type = 'Symbol', Data = '..'}
					end
				else
					toEmit = {Type = 'Symbol', Data = '.'}
				end

			elseif consume(':') then
				if consume(':') then
					toEmit = {Type = 'Symbol', Data = '::'}
				else
					toEmit = {Type = 'Symbol', Data = ':'}
				end

			elseif Symbols[c] then
				get()
				toEmit = {Type = 'Symbol', Data = c}

			else
				local contents, all = tryGetLongString()
				if contents then
					toEmit = {Type = 'String', Data = all, Constant = contents}
				else
					generateError("Unexpected Symbol `"..c.."` in source.", 2)
				end
			end

			--add the emitted symbol, after adding some common data
			toEmit.LeadingWhite = leadingWhite
			toEmit.Line = thisLine
			toEmit.Char = thisChar
			toEmit.Print = function()
				return "<"..(toEmit.Type..string.rep(' ', 7-#toEmit.Type)).."	"..(toEmit.Data or '').." >"
			end
			tokens[#tokens+1] = toEmit

			--halt after eof has been emitted
			if toEmit.Type == 'Eof' then break end
		end
	end)
	if not st then
		return false, err
	end

	--public interface:
	local tok = {}
	local savedP = {}
	local p = 1

	--getters
	function tok:Peek(n)
		n = n or 0
		return tokens[math.min(#tokens, p+n)]
	end
	function tok:Get()
		local t = tokens[p]
		p = math.min(p + 1, #tokens)
		return t
	end
	function tok:Is(t)
		return tok:Peek().Type == t
	end

	--save / restore points in the stream
	function tok:Save()
		savedP[#savedP+1] = p
	end
	function tok:Commit()
		savedP[#savedP] = nil
	end
	function tok:Restore()
		p = savedP[#savedP]
		savedP[#savedP] = nil
	end

	--either return a symbol if there is one, or return true if the requested
	--symbol was gotten.
	function tok:ConsumeSymbol(symb)
		local t = self:Peek()
		if t.Type == 'Symbol' then
			if symb then
				if t.Data == symb then
					self:Get()
					return true
				else
					return nil
				end
			else
				self:Get()
				return t
			end
		else
			return nil
		end
	end

	function tok:ConsumeKeyword(kw)
		local t = self:Peek()
		if t.Type == 'Keyword' and t.Data == kw then
			self:Get()
			return true
		else
			return nil
		end
	end

	function tok:IsKeyword(kw)
		local t = tok:Peek()
		return t.Type == 'Keyword' and t.Data == kw
	end

	function tok:IsSymbol(s)
		local t = tok:Peek()
		return t.Type == 'Symbol' and t.Data == s
	end

	function tok:IsEof()
		return tok:Peek().Type == 'Eof'
	end

	return true, tok
end


local ScopeContainer = {}
local GlobalVarGetMap = {}
local function ParseLua(src)
	ScopeContainer = {}
	local st, tok = LexLua(src)
	if not st then
		return false, tok
	end
	--
	local function GenerateError(msg)
		local err = ">> :"..tok:Peek().Line..":"..tok:Peek().Char..": "..msg.."\n"
		--find the line
		local lineNum = 0
		for line in src:gmatch("[^\n]*\n?") do
			if line:sub(-1,-1) == '\n' then line = line:sub(1,-2) end
			lineNum = lineNum+1
			if lineNum == tok:Peek().Line then
				err = err..">> `"..line:gsub('\t','		').."`\n"
				for i = 1, tok:Peek().Char do
					local c = line:sub(i,i)
					if c == '\t' then 
						err = err..'		'
					else
						err = err..' '
					end
				end
				err = err.."	 ^---"
				break
			end
		end
		return err
	end
	--
	GlobalVarGetMap = {}
	local function CreateScope(parent)
		local scope = {}
		scope.Parent = parent
		scope.LocalList = {}
		scope.LocalMap = {}
		scope.AccessedLocals = {}
		scope.Line = tok:Peek().Line
		function scope:GetLocal(name)
			scope.AccessedLocals[name] = true
			--first, try to get my variable 
			local my = scope.LocalMap[name]
			if my then return my end

			--next, try parent
			if scope.Parent then
				local par = scope.Parent:GetLocal(name)
				if par then return par end
			end

			return nil
		end
		function scope:CreateLocal(name)
			--create my own var
			local my = {}
			my.Scope = scope
			my.Name = name
			my.CanRename = true
			--
			scope.LocalList[#scope.LocalList+1] = my
			scope.LocalMap[name] = my
			--
			return my
		end
		local r = math.random(1e6,1e7-1)
		scope.Print = function() return "<Scope " .. r .. ">" end
		ScopeContainer[#ScopeContainer+1] = scope
		return scope
	end

	local ParseExpr;
	local ParseStatementList;

	local function ParseFunctionArgsAndBody(scope)
		local funcScope = CreateScope(scope)
		if not tok:ConsumeSymbol('(') then
			return false, GenerateError("`(` expected.")
		end

		--arg list
		local argList = {}
		local isVarArg = false
		while not tok:ConsumeSymbol(')') do
			if tok:Is('Ident') then
				local arg = funcScope:CreateLocal(tok:Get().Data)
				argList[#argList+1] = arg
				if not tok:ConsumeSymbol(',') then
					if tok:ConsumeSymbol(')') then
						break
					else
						return false, GenerateError("`)` expected.")
					end
				end
			elseif tok:ConsumeSymbol('...') then
				isVarArg = true
				if not tok:ConsumeSymbol(')') then
					return false, GenerateError("`...` must be the last argument of a function.")
				end
				break
			else
				return false, GenerateError("Argument name or `...` expected")
			end
		end

		--body
		local st, body = ParseStatementList(funcScope)
		if not st then return false, body end

		--end
		if not tok:ConsumeKeyword('end') then
			return false, GenerateError("`end` expected after function body")
		end

		local nodeFunc = {}
		nodeFunc.AstType = 'Function'
		nodeFunc.Scope = funcScope
		nodeFunc.Arguments = argList
		nodeFunc.Body = body
		nodeFunc.VarArg = isVarArg
		--
		return true, nodeFunc
	end


	local function ParsePrimaryExpr(scope)
		if tok:ConsumeSymbol('(') then
			local st, ex = ParseExpr(scope)
			if not st then return false, ex end
			if not tok:ConsumeSymbol(')') then
				return false, GenerateError("`)` Expected.")
			end
			--save the information about parenthesized expressions somewhere
			ex.ParenCount = (ex.ParenCount or 0) + 1
			return true, ex

		elseif tok:Is('Ident') then
			local id = tok:Get()
			local var = scope:GetLocal(id.Data)
			if not var then
				GlobalVarGetMap[id.Data] = true
			end
			--
			local nodePrimExp = {}
			nodePrimExp.AstType = 'VarExpr'
			nodePrimExp.Name = id.Data
			nodePrimExp.Local = var
			--
			return true, nodePrimExp
		else
			return false, GenerateError("primary expression expected")
		end
	end


	local function ParseSuffixedExpr(scope, onlyDotColon)
		--base primary expression
		local st, prim = ParsePrimaryExpr(scope)
		if not st then return false, prim end
		--
		while true do
			if tok:IsSymbol('.') or tok:IsSymbol(':') then
				local symb = tok:Get().Data
				if symb == ":" then
					-- scope:CreateLocal("self")
				end
				if not tok:Is('Ident') then
					return false, GenerateError("<Ident> expected.")
				end
				local id = tok:Get()
				local nodeIndex = {}
				nodeIndex.AstType = 'MemberExpr'
				nodeIndex.Base = prim
				nodeIndex.Indexer = symb
				nodeIndex.Ident = id
				--
				prim = nodeIndex

			elseif not onlyDotColon and tok:ConsumeSymbol('[') then
				local st, ex = ParseExpr(scope)
				if not st then return false, ex end
				if not tok:ConsumeSymbol(']') then
					return false, GenerateError("`]` expected.")
				end
				local nodeIndex = {}
				nodeIndex.AstType = 'IndexExpr'
				nodeIndex.Base = prim
				nodeIndex.Index = ex
				--
				prim = nodeIndex

			elseif not onlyDotColon and tok:ConsumeSymbol('(') then
				local args = {}
				while not tok:ConsumeSymbol(')') do
					local st, ex = ParseExpr(scope)
					if not st then return false, ex end
					args[#args+1] = ex
					if not tok:ConsumeSymbol(',') then
						if tok:ConsumeSymbol(')') then
							break
						else
							return false, GenerateError("`)` Expected.")
						end
					end
				end
				local nodeCall = {}
				nodeCall.AstType = 'CallExpr'
				nodeCall.Base = prim
				nodeCall.Arguments = args
				--
				prim = nodeCall

			elseif not onlyDotColon and tok:Is('String') then
				--string call
				local nodeCall = {}
				nodeCall.AstType = 'StringCallExpr'
				nodeCall.Base = prim
				nodeCall.Arguments	= {tok:Get()}
				--
				prim = nodeCall

			elseif not onlyDotColon and tok:IsSymbol('{') then
				--table call
				local st, ex = ParseExpr(scope)
				if not st then return false, ex end
				local nodeCall = {}
				nodeCall.AstType = 'TableCallExpr'
				nodeCall.Base = prim
				nodeCall.Arguments = {ex}
				--
				prim = nodeCall

			else
				break
			end
		end
		return true, prim
	end


	local function ParseSimpleExpr(scope)
		if tok:Is('Number') then
			local nodeNum = {}
			nodeNum.AstType = 'NumberExpr'
			nodeNum.Value = tok:Get()
			return true, nodeNum

		elseif tok:Is('String') then
			local nodeStr = {}
			nodeStr.AstType = 'StringExpr'
			nodeStr.Value = tok:Get()
			return true, nodeStr

		elseif tok:ConsumeKeyword('nil') then
			local nodeNil = {}
			nodeNil.AstType = 'NilExpr'
			return true, nodeNil

		elseif tok:IsKeyword('false') or tok:IsKeyword('true') then
			local nodeBoolean = {}
			nodeBoolean.AstType = 'BooleanExpr'
			nodeBoolean.Value = (tok:Get().Data == 'true')
			return true, nodeBoolean

		elseif tok:ConsumeSymbol('...') then
			local nodeDots = {}
			nodeDots.AstType = 'DotsExpr'
			return true, nodeDots

		elseif tok:ConsumeSymbol('{') then
			local v = {}
			v.AstType = 'ConstructorExpr'
			v.EntryList = {}
			--
			while true do
				if tok:IsSymbol('[') then
					--key
					tok:Get()
					local st, key = ParseExpr(scope)
					if not st then 
						return false, GenerateError("Key Expression Expected")
					end
					if not tok:ConsumeSymbol(']') then
						return false, GenerateError("`]` Expected")
					end
					if not tok:ConsumeSymbol('=') then
						return false, GenerateError("`=` Expected")
					end
					local st, value = ParseExpr(scope)
					if not st then
						return false, GenerateError("Value Expression Expected")
					end
					v.EntryList[#v.EntryList+1] = {
						Type = 'Key';
						Key = key;
						Value = value;
					}

				elseif tok:Is('Ident') then
					--value or key
					local lookahead = tok:Peek(1)
					if lookahead.Type == 'Symbol' and lookahead.Data == '=' then
						--we are a key
						local key = tok:Get() 
						if not tok:ConsumeSymbol('=') then
							return false, GenerateError("`=` Expected")
						end
						local st, value = ParseExpr(scope)
						if not st then
							return false, GenerateError("Value Expression Expected")
						end
						v.EntryList[#v.EntryList+1] = {
							Type = 'KeyString';
							Key = key.Data;
							Value = value; 
						}

					else
						--we are a value
						local st, value = ParseExpr(scope)
						if not st then
							return false, GenerateError("Value Exected")
						end
						v.EntryList[#v.EntryList+1] = {
							Type = 'Value';
							Value = value;
						}

					end
				elseif tok:ConsumeSymbol('}') then
					break

				else
					--value
					local st, value = ParseExpr(scope)
					v.EntryList[#v.EntryList+1] = {
						Type = 'Value';
						Value = value;
					}
					if not st then
						return false, GenerateError("Value Expected")
					end
				end

				if tok:ConsumeSymbol(';') or tok:ConsumeSymbol(',') then
					--all is good
				elseif tok:ConsumeSymbol('}') then
					break
				else
					return false, GenerateError("`}` or table entry Expected")
				end
			end
			return true, v

		elseif tok:ConsumeKeyword('function') then
			local st, func = ParseFunctionArgsAndBody(scope)
			if not st then return false, func end
			--
			func.IsLocal = true
			return true, func

		else
			return ParseSuffixedExpr(scope)
		end
	end


	local unops = lookupify{'-', 'not', '#'}
	local unopprio = 8
	local priority = {
		['+'] = {6,6};
		['-'] = {6,6};
		['%'] = {7,7};
		['/'] = {7,7};
		['*'] = {7,7};
		['^'] = {10,9};
		['..'] = {5,4};
		['=='] = {3,3};
		['<'] = {3,3};
		['<='] = {3,3};
		['~='] = {3,3};
		['>'] = {3,3};
		['>='] = {3,3};
		['and'] = {2,2};
		['or'] = {1,1};
	}
	local function ParseSubExpr(scope, level)
		--base item, possibly with unop prefix
		local st, exp
		if unops[tok:Peek().Data] then
			local op = tok:Get().Data
			st, exp = ParseSubExpr(scope, unopprio)
			if not st then return false, exp end
			local nodeEx = {}
			nodeEx.AstType = 'UnopExpr'
			nodeEx.Rhs = exp
			nodeEx.Op = op
			exp = nodeEx
		else
			st, exp = ParseSimpleExpr(scope)
			if not st then return false, exp end
		end

		--next items in chain
		while true do
			local prio = priority[tok:Peek().Data]
			if prio and prio[1] > level then
				local op = tok:Get().Data
				local st, rhs = ParseSubExpr(scope, prio[2])
				if not st then return false, rhs end
				local nodeEx = {}
				nodeEx.AstType = 'BinopExpr'
				nodeEx.Lhs = exp
				nodeEx.Op = op
				nodeEx.Rhs = rhs
				--
				exp = nodeEx
			else
				break
			end
		end

		return true, exp
	end


	ParseExpr = function(scope)
		return ParseSubExpr(scope, 0)
	end


	local function ParseStatement(scope)
		local stat = nil
		if tok:ConsumeKeyword('if') then
			--setup
			local nodeIfStat = {}
			nodeIfStat.AstType = 'IfStatement'
			nodeIfStat.Clauses = {}

			--clauses
			repeat
				local st, nodeCond = ParseExpr(scope)
				if not st then return false, nodeCond end
				if not tok:ConsumeKeyword('then') then
					return false, GenerateError("`then` expected.")
				end
				local st, nodeBody = ParseStatementList(scope)
				if not st then return false, nodeBody end
				nodeIfStat.Clauses[#nodeIfStat.Clauses+1] = {
					Condition = nodeCond;
					Body = nodeBody;
				}
			until not tok:ConsumeKeyword('elseif')

			--else clause
			if tok:ConsumeKeyword('else') then
				local st, nodeBody = ParseStatementList(scope)
				if not st then return false, nodeBody end
				nodeIfStat.Clauses[#nodeIfStat.Clauses+1] = {
					Body = nodeBody;
				}
			end

			--end
			if not tok:ConsumeKeyword('end') then
				return false, GenerateError("`end` expected.")
			end

			stat = nodeIfStat

		elseif tok:ConsumeKeyword('while') then
			--setup
			local nodeWhileStat = {}
			nodeWhileStat.AstType = 'WhileStatement'

			--condition
			local st, nodeCond = ParseExpr(scope)
			if not st then return false, nodeCond end

			--do
			if not tok:ConsumeKeyword('do') then
				return false, GenerateError("`do` expected.")
			end

			--body
			local st, nodeBody = ParseStatementList(scope)
			if not st then return false, nodeBody end

			--end
			if not tok:ConsumeKeyword('end') then
				return false, GenerateError("`end` expected.")
			end

			--return
			nodeWhileStat.Condition = nodeCond
			nodeWhileStat.Body = nodeBody
			stat = nodeWhileStat

		elseif tok:ConsumeKeyword('do') then
			--do block
			local st, nodeBlock = ParseStatementList(scope)
			if not st then return false, nodeBlock end
			if not tok:ConsumeKeyword('end') then
				return false, GenerateError("`end` expected.")
			end

			local nodeDoStat = {}
			nodeDoStat.AstType = 'DoStatement'
			nodeDoStat.Body = nodeBlock
			stat = nodeDoStat

		elseif tok:ConsumeKeyword('for') then
			--for block
			if not tok:Is('Ident') then
				return false, GenerateError("<ident> expected.")
			end
			local baseVarName = tok:Get()
			if tok:ConsumeSymbol('=') then
				--numeric for
				local forScope = CreateScope(scope)
				local forVar = forScope:CreateLocal(baseVarName.Data)
				--
				local st, startEx = ParseExpr(scope)
				if not st then return false, startEx end
				if not tok:ConsumeSymbol(',') then
					return false, GenerateError("`,` Expected")
				end
				local st, endEx = ParseExpr(scope)
				if not st then return false, endEx end
				local st, stepEx;
				if tok:ConsumeSymbol(',') then
					st, stepEx = ParseExpr(scope)
					if not st then return false, stepEx end
				end
				if not tok:ConsumeKeyword('do') then
					return false, GenerateError("`do` expected")
				end
				--
				local st, body = ParseStatementList(forScope)
				if not st then return false, body end
				if not tok:ConsumeKeyword('end') then
					return false, GenerateError("`end` expected")
				end
				--
				local nodeFor = {}
				nodeFor.AstType = 'NumericForStatement'
				nodeFor.Scope = forScope
				nodeFor.Variable = forVar
				nodeFor.Start = startEx
				nodeFor.End = endEx
				nodeFor.Step = stepEx
				nodeFor.Body = body
				stat = nodeFor
			else
				--generic for
				local forScope = CreateScope(scope)
				--
				local varList = {forScope:CreateLocal(baseVarName.Data)}
				while tok:ConsumeSymbol(',') do
					if not tok:Is('Ident') then
						return false, GenerateError("for variable expected.")
					end
					varList[#varList+1] = forScope:CreateLocal(tok:Get().Data)
				end
				if not tok:ConsumeKeyword('in') then
					return false, GenerateError("`in` expected.")
				end
				local generators = {}
				local st, firstGenerator = ParseExpr(scope)
				if not st then return false, firstGenerator end
				generators[#generators+1] = firstGenerator
				while tok:ConsumeSymbol(',') do
					local st, gen = ParseExpr(scope)
					if not st then return false, gen end
					generators[#generators+1] = gen
				end
				if not tok:ConsumeKeyword('do') then
					return false, GenerateError("`do` expected.")
				end
				local st, body = ParseStatementList(forScope)
				if not st then return false, body end
				if not tok:ConsumeKeyword('end') then
					return false, GenerateError("`end` expected.")
				end
				--
				local nodeFor = {}
				nodeFor.AstType = 'GenericForStatement'
				nodeFor.Scope = forScope
				nodeFor.VariableList = varList
				nodeFor.Generators = generators
				nodeFor.Body = body
				stat = nodeFor
			end

		elseif tok:ConsumeKeyword('repeat') then
			local st, body = ParseStatementList(scope)
			if not st then return false, body end
			--
			if not tok:ConsumeKeyword('until') then
				return false, GenerateError("`until` expected.")
			end
			--
			local st, cond = ParseExpr(scope)
			if not st then return false, cond end
			--
			local nodeRepeat = {}
			nodeRepeat.AstType = 'RepeatStatement'
			nodeRepeat.Condition = cond
			nodeRepeat.Body = body
			stat = nodeRepeat

		elseif tok:ConsumeKeyword('function') then
			if not tok:Is('Ident') then
				return false, GenerateError("Function name expected")
			end
			local st, name = ParseSuffixedExpr(scope, true) --true => only dots and colons
			if not st then return false, name end
			--
			local st, func = ParseFunctionArgsAndBody(scope)
			if not st then return false, func end
			--
			func.IsLocal = false
			func.Name = name
			stat = func

		elseif tok:ConsumeKeyword('local') then
			if tok:Is('Ident') then
				local varList = {tok:Get().Data}
				while tok:ConsumeSymbol(',') do
					if not tok:Is('Ident') then
						return false, GenerateError("local var name expected")
					end
					varList[#varList+1] = tok:Get().Data
				end

				local initList = {}
				if tok:ConsumeSymbol('=') then
					repeat
						local st, ex = ParseExpr(scope)
						if not st then return false, ex end
						initList[#initList+1] = ex
					until not tok:ConsumeSymbol(',')
				end

				--now patch var list
				--we can't do this before getting the init list, because the init list does not
				--have the locals themselves in scope.
				for i, v in pairs(varList) do
					varList[i] = scope:CreateLocal(v)
				end

				local nodeLocal = {}
				nodeLocal.AstType = 'LocalStatement'
				nodeLocal.LocalList = varList
				nodeLocal.InitList = initList
				--
				stat = nodeLocal

			elseif tok:ConsumeKeyword('function') then
				if not tok:Is('Ident') then
					return false, GenerateError("Function name expected")
				end
				local name = tok:Get().Data
				local localVar = scope:CreateLocal(name)
				--	
				local st, func = ParseFunctionArgsAndBody(scope)
				if not st then return false, func end
				--
				func.Name = localVar
				func.IsLocal = true
				stat = func

			else
				return false, GenerateError("local var or function def expected")
			end

		elseif tok:ConsumeKeyword('return') then
			local exList = {}
			if not tok:IsKeyword('end') then
				local st, firstEx = ParseExpr(scope)
				if st then 
					exList[1] = firstEx
					while tok:ConsumeSymbol(',') do
						local st, ex = ParseExpr(scope)
						if not st then return false, ex end
						exList[#exList+1] = ex
					end
				end
			end

			local nodeReturn = {}
			nodeReturn.AstType = 'ReturnStatement'
			nodeReturn.Arguments = exList
			stat = nodeReturn

		elseif tok:ConsumeKeyword('break') then
			local nodeBreak = {}
			nodeBreak.AstType = 'BreakStatement'
			stat = nodeBreak

		else
			--statementParseExpr
			local st, suffixed = ParseSuffixedExpr(scope)
			if not st then return false, suffixed end

			--assignment or call?
			if tok:IsSymbol(',') or tok:IsSymbol('=') then
				--check that it was not parenthesized, making it not an lvalue
				if (suffixed.ParenCount or 0) > 0 then
					return false, GenerateError("Can not assign to parenthesized expression, is not an lvalue")
				end

				--more processing needed
				local lhs = {suffixed}
				while tok:ConsumeSymbol(',') do
					local st, lhsPart = ParseSuffixedExpr(scope)
					if not st then return false, lhsPart end
					lhs[#lhs+1] = lhsPart
				end

				--equals
				if not tok:ConsumeSymbol('=') then
					return false, GenerateError("`=` Expected.")
				end

				--rhs
				local rhs = {}
				local st, firstRhs = ParseExpr(scope)
				if not st then return false, firstRhs end
				rhs[1] = firstRhs
				while tok:ConsumeSymbol(',') do
					local st, rhsPart = ParseExpr(scope)
					if not st then return false, rhsPart end
					rhs[#rhs+1] = rhsPart
				end

				--done
				local nodeAssign = {}
				nodeAssign.AstType = 'AssignmentStatement'
				nodeAssign.Lhs = lhs
				nodeAssign.Rhs = rhs
				stat = nodeAssign

			elseif suffixed.AstType == 'CallExpr' or 
						 suffixed.AstType == 'TableCallExpr' or 
						 suffixed.AstType == 'StringCallExpr' 
			then
				--it's a call statement
				local nodeCall = {}
				nodeCall.AstType = 'CallStatement'
				nodeCall.Expression = suffixed
				stat = nodeCall
			else
				return false, GenerateError("Assignment Statement Expected")
			end
		end

		stat.HasSemicolon = tok:ConsumeSymbol(';')
		return true, stat
	end


	local statListCloseKeywords = lookupify{'end', 'else', 'elseif', 'until'}
	ParseStatementList = function(scope)
		local nodeStatlist = {}
		nodeStatlist.Scope = CreateScope(scope)
		nodeStatlist.AstType = 'Statlist'
		--
		local stats = {}
		--
		while not statListCloseKeywords[tok:Peek().Data] and not tok:IsEof() do
			local st, nodeStatement = ParseStatement(nodeStatlist.Scope)
			if not st then return false, nodeStatement end
			stats[#stats+1] = nodeStatement
		end
		--
		nodeStatlist.Body = stats
		return true, nodeStatlist
	end


	local function mainfunc()
		local topScope = CreateScope()
		return ParseStatementList(topScope)
	end

	local st, main = mainfunc()
	return st, main
end


--Module entry point
local function run(C)
	if type(C) == "string" then
		local page = mw.title.new(C)
		if not page then
			error("Failed to grab the page '"..C.."'")
			return false,"Failed to grab page"
		end
		C = page:getContent() or ""
	elseif type(C) == "table" then --Assume a title object
		C = C:getContent() or ""
	elseif C == nil then
		C = mw.title.getCurrentTitle():getContent() or ""
	else
		error("Unrecognised input type '"..type(C).."'")
	end

	if C == "" then
		print("No lua to parse from the given input")
	end
	local s,p = ParseLua(C)
	if not s then
		error("Failed to parse the lua - "..p)
	end

	local ignoredUnderscores = 0
	for i,scope in pairs(ScopeContainer) do
		for Local,_ in pairs(scope.LocalMap) do
			if not scope.AccessedLocals[Local] then
				if Local == "_" then
					ignoredUnderscores = ignoredUnderscores + 1
				else
					if scope.Line == 1 then
						print("Local variable '"..Local.."' in the main scope is defined but never referenced")
					else
						print("Local variable '"..Local.."' in the scope starting on line "..scope.Line.." is defined but never referenced")
					end
				end
			elseif Local == "_" then
				print("Local variable '_' in the scope staring on line "..scope.Line.." is referenced, despite the name implying it is unused")
			end
		end
	end
	if ignoredUnderscores > 1 then
		print(ignoredUnderscores.." local variables called '_' were defined but never referenced, likely intentionally")
	elseif ignoredUnderscores == 1 then
		print("1 local variable called '_' was defined but never referenced, likely intentionally")
	end
	for global,_ in pairs(GlobalVarGetMap) do
		if not rawget(_G,global) and global ~= "self" then --self picking up wrongly is an issue in the parser, and generally not an expected global name, so we lazy ignore
			print("Global variable '"..global.."' was referenced or defined, yet isn't in _G")
		end
	end
	print("Analysis finished")
end

--Template entry point
local function main(frame)
	local page = frame:getTitle()
	if frame.args[1] and frame.args[1] ~= "" then
		page = frame.args[1]
	end
	local title = mw.title.new(page)
	if not title then
		error("Unable to fetch content for page '"..page.."'")
	end

	local C = title:getContent() or ""
	if C == "" then
		return "<span class='error'>No lua to parse in page '"..page.."'</span>"
	end
	local s,p = ParseLua(C)
	if not s then
		error("Failed to parse the lua - "..p)
	end

	local tableContent = '{| class="wikitable sortable"\n! style="text-align:center" colspan=3 | Basic code analysis for [[' .. page .. ']]' ..
		' <span style="font-size:80%">[[Module:Sandbox/Aidan9382/CodeAnalysis|v]]</span>' ..
		'\n|-\n! Scope !! Message'
	local ignoredUnderscores = 0
	for i,scope in pairs(ScopeContainer) do
		for Local,_ in pairs(scope.LocalMap) do
			local tableLine = ""
			if not scope.AccessedLocals[Local] then
				if Local == "_" then
					ignoredUnderscores = ignoredUnderscores + 1
				else
					if scope.Line == 1 then
						tableLine = "\n|-\n| Main scope || <code>"..Local.."</code> is defined but never referenced"
					else
						tableLine = "\n|-\n| Scope starting line "..scope.Line.." || <code>"..Local.."</code> is defined but never referenced"
					end
				end
			elseif Local == "_" then
				tableLine = "\n|-\n| Scope starting line "..scope.Line.." || Variable <code>_</code> is referenced, despite the name implying it is unused"
			end
			if tableLine ~= "" then
				tableContent = tableContent .. tableLine
			end
		end
	end
	if ignoredUnderscores > 1 then
		tableContent = tableContent .. "\n|-\n| Entire script || "..ignoredUnderscores.." local variables called <code>_</code> were defined but never referenced, likely intentionally"
	elseif ignoredUnderscores == 1 then
		tableContent = tableContent .. "\n|-\n| Entire script || 1 local variable called <code>_</code> was defined but never referenced, likely intentionally"
	end
	for global,_ in pairs(GlobalVarGetMap) do
		if not rawget(_G,global) and global ~= "self" then --self picking up wrongly is an issue in the parser, and generally not an expected global name, so we lazily ignore
			tableContent = tableContent .. "\n|-\n| Entire script || Global variable <code>"..global.."</code> was referenced or defined, yet isn't in _G"
		end
	end
	return tableContent .. "\n|}"
end

return setmetatable({
	run = run,
	main = main
}, {
	__call = function(self, C)
		return run(C)
	end
})
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