diff --git a/test/jstests/unshift.py b/test/jstests/unshift.py
index de76f2cab..02ab96874 100644
--- a/test/jstests/unshift.py
+++ b/test/jstests/unshift.py
@@ -1,6 +1,4 @@
 
-skip = {'p': 'Signed integers not yet supported'}
-
 tests = [
     {
         'code': '''
diff --git a/youtube_dl/jsinterp/jsgrammar.py b/youtube_dl/jsinterp/jsgrammar.py
index b44714bcb..a306df770 100644
--- a/youtube_dl/jsinterp/jsgrammar.py
+++ b/youtube_dl/jsinterp/jsgrammar.py
@@ -6,7 +6,7 @@ from collections import namedtuple
 
 _token_keys = ('COPEN', 'CCLOSE', 'POPEN', 'PCLOSE', 'SOPEN', 'SCLOSE',
                'DOT', 'END', 'COMMA', 'HOOK', 'COLON',
-               'AND', 'OR', 'INC', 'DEC', 'NOT', 'BNOT', 'DEL', 'VOID', 'TYPE',
+               'AND', 'OR', 'PLUS', 'NEG', 'INC', 'DEC', 'NOT', 'BNOT', 'DEL', 'VOID', 'TYPE',
                'LT', 'GT', 'LE', 'GE', 'EQ', 'NE', 'SEQ', 'SNE', 'IN', 'INSTANCEOF',
                'BOR', 'BXOR', 'BAND', 'RSHIFT', 'LSHIFT', 'URSHIFT', 'SUB', 'ADD', 'MOD', 'DIV', 'MUL',
                'OP', 'AOP', 'UOP', 'LOP', 'REL',
@@ -48,7 +48,6 @@ _SINGLE_QUOTED_RE = r"""'(?:(?:\\'|\n)|[^'\n])*'"""
 _DOUBLE_QUOTED_RE = r'''"(?:(?:\\"|\n)|[^"\n])*"'''
 _STRING_RE = r'(?:%s)|(?:%s)' % (_SINGLE_QUOTED_RE, _DOUBLE_QUOTED_RE)
 
-# FIXME signed values
 _INTEGER_RE = r'(?:%(hex)s)|(?:%(dec)s)|(?:%(oct)s)' % {'hex': __HEXADECIMAL_RE, 'dec': __DECIMAL_RE, 'oct': __OCTAL_RE}
 _FLOAT_RE = r'(?:(?:%(dec)s\.[0-9]*)|(?:\.[0-9]+))(?:[eE][+-]?[0-9]+)?' % {'dec': __DECIMAL_RE}
 
@@ -62,15 +61,10 @@ _NULL_RE = r'null'
 _REGEX_FLAGS_RE = r'(?![gimy]*(?P<reflag>[gimy])[gimy]*(?P=reflag))(?P<%s>[gimy]{0,4}\b)' % 'REFLAGS'
 _REGEX_RE = r'/(?!\*)(?P<%s>(?:[^/\n]|(?:\\/))*)/(?:(?:%s)|(?:\s|$))' % ('REBODY', _REGEX_FLAGS_RE)
 
-_TOKENS = [
-    (Token.NULL, _NULL_RE),
-    (Token.BOOL, _BOOL_RE),
-    (Token.ID, _NAME_RE),
-    (Token.STR, _STRING_RE),
-    (Token.INT, _INTEGER_RE),
-    (Token.FLOAT, _FLOAT_RE),
-    (Token.REGEX, _REGEX_RE)
-]
+token_keys = Token.NULL, Token.BOOL, Token.ID, Token.STR, Token.INT, Token.FLOAT, Token.REGEX
+
+_TOKENS = zip(token_keys, (_NULL_RE, _BOOL_RE, _NAME_RE, _STRING_RE, _INTEGER_RE, _FLOAT_RE, _REGEX_RE))
+
 
 COMMENT_RE = r'(?P<%s>/\*(?:(?!\*/)(?:\n|.))*\*/)' % Token.COMMENT
 TOKENS_RE = r'|'.join('(?P<%(id)s>%(value)s)' % {'id': name, 'value': value}
diff --git a/youtube_dl/jsinterp/jsinterp.py b/youtube_dl/jsinterp/jsinterp.py
index 52e3dc2bf..dae614945 100644
--- a/youtube_dl/jsinterp/jsinterp.py
+++ b/youtube_dl/jsinterp/jsinterp.py
@@ -4,9 +4,7 @@ import re
 
 from ..utils import ExtractorError
 from .tstream import TokenStream
-from .jsgrammar import Token
-
-_token_keys = set((Token.NULL, Token.BOOL, Token.ID, Token.STR, Token.INT, Token.FLOAT, Token.REGEX))
+from .jsgrammar import Token, token_keys
 
 
 class Context(object):
@@ -497,7 +495,7 @@ class JSInterpreter(object):
 
         # TODO support let
         peek_id, peek_value, peek_pos = token_stream.peek()
-        if peek_id in _token_keys:
+        if peek_id in token_keys:
             if peek_id is Token.ID:
                 # this
                 if peek_value == 'this':
@@ -924,7 +922,7 @@ class JSInterpreter(object):
                    self.global_vars[expr[1]])
         
         # literal
-        elif name in _token_keys:
+        elif name in token_keys:
             ref = Reference(expr[1])
 
         elif name is Token.ARRAY:
diff --git a/youtube_dl/jsinterp/tstream.py b/youtube_dl/jsinterp/tstream.py
index 36a22d09e..50c137894 100644
--- a/youtube_dl/jsinterp/tstream.py
+++ b/youtube_dl/jsinterp/tstream.py
@@ -13,7 +13,8 @@ from .jsgrammar import (
     RELATIONS_RE,
     ASSIGN_OPERATORS_RE,
     OPERATORS_RE,
-    Token
+    Token,
+    token_keys
 )
 
 _PUNCTUATIONS = {
@@ -34,10 +35,12 @@ _LOGICAL_OPERATORS = {
     '||': (Token.OR, lambda cur, right: cur or right)
 }
 _UNARY_OPERATORS = {
+    '+': (Token.PLUS, lambda cur: cur),
+    '-': (Token.NEG, lambda cur: cur * -1),
     '++': (Token.INC, lambda cur: cur + 1),
     '--': (Token.DEC, lambda cur: cur - 1),
     '!': (Token.NOT, operator.not_),
-    '~': (Token.BNOT, lambda cur: cur ^ -1),
+    '~': (Token.BNOT, operator.invert),
     # XXX define these operators
     'delete': (Token.DEL, None),
     'void': (Token.VOID, None),
@@ -53,9 +56,8 @@ _RELATIONS = {
     '!=': (Token.NE, operator.ne),
     '===': (Token.SEQ, lambda cur, right: cur == right and type(cur) == type(right)),
     '!==': (Token.SNE, lambda cur, right: not cur == right or not type(cur) == type(right)),
-    # XXX define instanceof and in operators
-    'in': (Token.IN, None),
-    'instanceof': (Token.INSTANCEOF, None)
+    'in': (Token.IN, operator.contains),
+    'instanceof': (Token.INSTANCEOF, lambda cur, right: isinstance(cur, right))
 }
 _OPERATORS = {
     '|': (Token.BOR, operator.or_),
@@ -124,7 +126,6 @@ class TokenStream(object):
                 elif token_id is Token.STR:
                     yield (token_id, token_value[1:-1], pos)
                 elif token_id is Token.INT:
-                    # FIXME signed values
                     root = ((16 if len(token_value) > 2 and token_value[1] in 'xX' else 8)
                             if token_value.startswith('0') else 10)
                     yield (token_id, int(token_value, root), pos)
@@ -137,6 +138,10 @@ class TokenStream(object):
                 elif token_id is Token.ID:
                     yield (token_id, token_value, pos)
                 elif token_id in _operator_lookup:
+                    # FIXME signed values
+                    if (token_id is Token.OP and token_value in ('-', '+') and
+                            self._last[0] not in token_keys and self._last[0] is not Token.PCLOSE):
+                        token_id = Token.UOP
                     yield (token_id if token_value != 'in' else Token.IN,
                            _operator_lookup[token_id][token_value],
                            pos)