Working on compiler

compiler.lua

@@ -0,0 +1,166 @@
+--~ t = debug.getmetatable ("")
+--~ t.__index = function(self,k)
+--~ 	if type(k)=="number" then
+--~ 		return string.sub(self,k,k)
+--~ 	end
+--~ end
+Token = {}
+Token.__index = Token
+local INTEGER, PLUS, EOF, MINUS, MUL, DIV, LPAREN, RPAREN = "INT","+","EOF", "-", "*", "/", "(", ")"
+function Token.__tostring(self)
+	return string.format("Token(%s, %s)",self.type,self.value)
+end
+function Token:new(tp,val)
+	local c = {}
+	setmetatable(c,self)
+	c.type = tp
+	c.value = val
+	print("Token:"..tp)
+	return c
+end
+
+Lexer = {}
+Lexer.__index = Lexer
+function Lexer:new(text)
+	local c = {}
+	setmetatable(c,self)
+	self.text = text
+	self.pos = 1
+	self.current_char = self.text:sub(1,1)
+	self.stop = false
+	return c
+end
+function Lexer:advance()
+	self.pos = self.pos + 1
+	if self.pos > #self.text then
+		self.current_char = false
+	else
+		self.current_char = self.text:sub(self.pos,self.pos)
+	end
+end
+function Lexer:error()
+	error("Invalid character")
+end
+function Lexer:skip_whitespace()
+	while self.current_char and self.current_char:match("%s") do
+		self:advance()
+	end
+end
+function Lexer:integer()
+	local result = {}
+	while self.current_char and self.current_char:match("%d") do
+		table.insert(result,self.current_char)
+		self:advance()
+	end
+	return tonumber(table.concat(result))
+end
+function Lexer:get_next_token()
+	while self.current_char do
+		::continue::
+		if self.current_char:match("%s") then
+			self:skip_whitespace()
+			goto continue
+		end
+		if self.current_char:match("%d") then
+			return Token:new(INTEGER,self:integer())
+		end
+		if self.current_char == "+" then
+			self:advance()
+			return Token:new(PLUS,"+")
+		end
+		if self.current_char == "-" then--55+77
+			self:advance()
+			return Token:new(MINUS,"-")
+		end
+		if self.current_char == "*" then
+			self:advance()
+			return Token:new(MUL,"*")
+		end
+		if self.current_char == "/" then
+			self:advance()
+			return Token:new(DIV,"/")
+		end
+		if self.current_char == "(" then
+			self:advance()
+			return Token:new(LPAREN,"(")
+		end
+		if self.current_char == ")" then
+			self:advance()
+			return Token:new(RPAREN,")")
+		end
+		self:error("Invalid Symbol!")
+	end
+	return Token:new(EOF, nil)
+end
+
+Interpreter = {}
+Interpreter.__index = Interpreter
+function Interpreter:new(lexer)
+	local c = {}
+	setmetatable(c,self)
+	c.lexer = lexer
+	c.current_token = c.lexer:get_next_token()
+	return c
+end
+function Interpreter:error()
+	error('Error Invalid Syntax')
+end
+function Interpreter:eat(token_type)
+	if self.current_token.type == token_type then
+		self.current_token = self.lexer:get_next_token()
+	else
+		self:error()
+	end
+end
+function Interpreter:factor()
+	local token = self.current_token
+	if token.type == INTEGER then
+		self:eat(INTEGER)
+		return token.value
+	elseif token.type == LPAREN then
+		self:eat(LPAREN)
+		local result = self:expr()
+		self:eat(RPAREN)
+		return result
+	end
+end
+function Interpreter:term()
+	local result = self:factor()
+	local token
+	while self.current_token.type == MUL or self.current_token.type == DIV do
+		token = self.current_token
+		if token.type == MUL then
+			self:eat(MUL)
+			result = result * self:factor()
+		elseif token.type == DIV then
+			self:eat(DIV)
+			result = result / self:factor()
+		end
+	end
+	return result
+end
+function Interpreter:expr()
+	local result = self:term()
+	local token
+	while self.current_token.type == PLUS or self.current_token.type == MINUS do
+		token = self.current_token
+		if token.type == PLUS then
+			self:eat(PLUS)
+			result = result + self:term()
+		elseif token.type == MINUS then
+			self:eat(MINUS)
+			result = result - self:term()
+		end
+	end
+	return result
+end
+while true do
+	io.write("calc> ")
+	local text = io.read()
+	if text then
+		l = Lexer:new(text)
+		i = Interpreter:new(l)
+		result = i:expr()
+		print(result)
+	end
+end

test.lua

@@ -1,5 +0,0 @@
-package.path = "./?/init.lua;"..package.path
-local pm = require("parseManager")
-state = pm:load("test.dms")
-print(state:dump())
-state:think()