diff --git a/parser.py b/parser.py
index 293bf77..8f3e5e4 100644
--- a/parser.py
+++ b/parser.py
@@ -1,20 +1,23 @@
 from __future__ import print_function
-from pprint import pprint
 from rply import ParserGenerator, LexerGenerator
 from rply.token import BaseBox
 
 lg = LexerGenerator()
 lg.add("LPAREN", r"\(")
 lg.add("RPAREN", r"\)")
+lg.add("QUOTE", r"'")
 lg.add("ATOM", r"[^\s()]+")
 lg.ignore(r"\s+")
 
-pg = ParserGenerator(["LPAREN", "RPAREN", "ATOM"])
+pg = ParserGenerator(["QUOTE", "LPAREN", "RPAREN", "ATOM"])
 
 
 @pg.error
 def error_handler(token):
-    raise ValueError("unexpected %s" % token.gettokentype())
+    type = token.gettokentype()
+    pos = token.getsourcepos()
+    raise ValueError("unexpected %s at (%s, %s)" %
+                     (type, pos.lineno, pos.colno))
 
 
 @pg.production("main : sexpr")
@@ -22,49 +25,52 @@ def main(p):
     return p[0]
 
 
-@pg.production("sexpr : LPAREN expr RPAREN")
+@pg.production("sexpr : ATOM")
+@pg.production("sexpr : QUOTE sexpr")
+@pg.production("sexpr : LPAREN list RPAREN")
 def sexpr(p):
-    return BoxSexpr(p[1])
+    if p[0].gettokentype() == "ATOM":
+        return BoxAtom(p[0].getstr())
+    elif p[0].gettokentype() == "QUOTE":
+        return BoxQuote(p[1])
+    else:
+        return p[1]
 
 
-@pg.production("expr : ATOM")
-def atom(p):
-    return BoxAtom(p[0].getstr())
-
-
-@pg.production("expr : ATOM sexpr")
-@pg.production("expr : ATOM expr")
-def sexpr(p):
-    return BoxExpr(BoxAtom(p[0].getstr()), p[1])
+@pg.production("list : sexpr")
+@pg.production("list : sexpr list")
+def list(p):
+    if len(p) == 1:
+        return BoxPair(p[0])
+    else:
+        return BoxPair(p[0], p[1])
 
 lexer = lg.build()
 parser = pg.build()
 
 
-class BoxSexpr(BaseBox):
-    def __init__(self, expr):
-        self.expr = expr
+class BoxQuote(BaseBox):
+    def __init__(self, sexpr):
+        self.sexpr = sexpr
 
-    def expr(self):
-        return self.expr
+    def sexpr(self):
+        return self.sexpr
 
     def __str__(self):
-        return "( %s )" % (self.expr)
+        return "' %s" % self.sexpr
 
 
-class BoxExpr(BaseBox):
-    def __init__(self, atom, expr):
-        self.atom = atom
-        self.expr = expr
-
-    def atom(self):
-        return self.atom
-
-    def expr(self):
-        return self.expr
+class BoxPair(BaseBox):
+    def __init__(self, x, y=None):
+        self.x = x
+        self.y = y
 
     def __str__(self):
-        return "%s . ( %s )" % (self.atom, self.expr)
+        if self.y is None:
+            y = "NIL"
+        else:
+            y = self.y
+        return "(%s . %s)" % (self.x, y)
 
 
 class BoxAtom(BaseBox):
@@ -77,4 +83,14 @@ class BoxAtom(BaseBox):
     def __str__(self):
         return "%s" % (self.atom)
 
+
+print(parser.parse(lexer.lex("1")))
+print(parser.parse(lexer.lex("'1")))
+print(parser.parse(lexer.lex("+")))
+print(parser.parse(lexer.lex("'+")))
+print(parser.parse(lexer.lex("(+ 1 2)")))
+print(parser.parse(lexer.lex("'(+ 1 2)")))
 print(parser.parse(lexer.lex("(+ 1 (* 3 2))")))
+print(parser.parse(lexer.lex("'(+ 1 (* 3 2))")))
+print(parser.parse(lexer.lex("(+ (* 4 5) (* 3 2))")))
+print(parser.parse(lexer.lex("(+ '(* 4 5) (* 3 2))")))