diff --git a/lib/liquid/lexer.rb b/lib/liquid/lexer.rb
index 0d011b18..d8d8b566 100644
--- a/lib/liquid/lexer.rb
+++ b/lib/liquid/lexer.rb
@@ -29,11 +29,12 @@ module Liquid
       '[' => :open_square,
       ']' => :close_square
     }
-    IDENTIFIER = /[\w\-]+/
+    IDENTIFIER = /[\w\-?]+/
     SINGLE_STRING_LITERAL = /'[^\']*'/
     DOUBLE_STRING_LITERAL = /"[^\"]*"/
     INTEGER_LITERAL = /-?\d+/
     FLOAT_LITERAL = /-?\d+(?:\.\d+)?/
+    COMPARISON_OPERATOR = /==|!=|<>|<=?|>=?|contains/
 
     def initialize(input)
       @ss = StringScanner.new(input)
@@ -57,21 +58,26 @@ module Liquid
       return if @ss.eos?
       
       case
+      when t = @ss.scan(COMPARISON_OPERATOR) then Token[:comparison, t]
       when t = @ss.scan(IDENTIFIER) then Token[:id, t]
       when t = @ss.scan(SINGLE_STRING_LITERAL) then Token[:string, t]
       when t = @ss.scan(DOUBLE_STRING_LITERAL) then Token[:string, t]
       when t = @ss.scan(INTEGER_LITERAL) then Token[:integer, t]
       when t = @ss.scan(FLOAT_LITERAL) then Token[:float, t]
       else
-        c = @ss.getch
-        if s = SPECIALS[c]
-          return Token[s,c]
-        end
-
-        raise SyntaxError, "Unexpected character #{c}."
+        lex_specials
       end
     end
 
+    def lex_specials
+      c = @ss.getch
+      if s = SPECIALS[c]
+        return Token[s,c]
+      end
+
+      raise SyntaxError, "Unexpected character #{c}."
+    end
+
     def consume_whitespace
       @ss.skip(/\s*/)
     end
diff --git a/lib/liquid/tags/if.rb b/lib/liquid/tags/if.rb
index e495a6bb..c5f455a4 100644
--- a/lib/liquid/tags/if.rb
+++ b/lib/liquid/tags/if.rb
@@ -45,7 +45,7 @@ module Liquid
         block = if tag == 'else'
           ElseCondition.new
         else
-          old_parse(markup)
+          parse_condition(markup)
         end
 
         @blocks.push(block)
@@ -81,12 +81,19 @@ module Liquid
           new_cond.send(op.to_sym, condition)
           condition = new_cond
         end
+        p.consume(:end_of_string)
 
         condition
       end
 
       def parse_comparison(p)
-        
+        a = p.expression
+        if op = p.consume?(:comparison)
+          b = p.expression
+          Condition.new(a, op, b)
+        else
+          Condition.new(a)
+        end
       end
   end
 
diff --git a/test/liquid/error_handling_test.rb b/test/liquid/error_handling_test.rb
index 22603bbb..6eb722a3 100644
--- a/test/liquid/error_handling_test.rb
+++ b/test/liquid/error_handling_test.rb
@@ -63,11 +63,8 @@ class ErrorHandlingTest < Test::Unit::TestCase
   end
 
   def test_unrecognized_operator
-    assert_nothing_raised do
-      template = Liquid::Template.parse(' {% if 1 =! 2 %}ok{% endif %} ')
-      assert_equal ' Liquid error: Unknown operator =! ', template.render
-      assert_equal 1, template.errors.size
-      assert_equal Liquid::ArgumentError, template.errors.first.class
+    assert_raise(SyntaxError) do
+      Liquid::Template.parse(' {% if 1 =! 2 %}ok{% endif %} ')
     end
   end
 
diff --git a/test/liquid/parsing_quirks_test.rb b/test/liquid/parsing_quirks_test.rb
index 9f393217..2ff95ec2 100644
--- a/test/liquid/parsing_quirks_test.rb
+++ b/test/liquid/parsing_quirks_test.rb
@@ -40,15 +40,20 @@ class ParsingQuirksTest < Test::Unit::TestCase
   end
 
   def test_meaningless_parens
-    assigns = {'b' => 'bar', 'c' => 'baz'}
-    markup = "a == 'foo' or (b == 'bar' and c == 'baz') or false"
-    assert_template_result(' YES ',"{% if #{markup} %} YES {% endif %}", assigns)
+    assert_raise(SyntaxError) do
+      markup = "a == 'foo' or (b == 'bar' and c == 'baz') or false"
+      Template.parse("{% if #{markup} %} YES {% endif %}")
+    end
   end
 
   def test_unexpected_characters_silently_eat_logic
-    markup = "true && false"
-    assert_template_result(' YES ',"{% if #{markup} %} YES {% endif %}")
-    markup = "false || true"
-    assert_template_result('',"{% if #{markup} %} YES {% endif %}")
+    assert_raise(SyntaxError) do
+      markup = "true && false"
+      Template.parse("{% if #{markup} %} YES {% endif %}")
+    end
+    assert_raise(SyntaxError) do
+      markup = "false || true"
+      Template.parse("{% if #{markup} %} YES {% endif %}")
+    end
   end
 end # ParsingQuirksTest