diff --git a/.travis.yml b/.travis.yml
index 013ec4d..c4eb50c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -13,3 +13,6 @@ rvm:
 - 1.9.2
 - 1.9.3
 - 2.0.0
+- 2.2.8
+- 2.3.5
+- 2.4.2
diff --git a/Manifest.txt b/Manifest.txt
index 81748d5..0570881 100644
--- a/Manifest.txt
+++ b/Manifest.txt
@@ -1,12 +1,15 @@
 .autotest
+.bundle/config
 .hoeignore
 .travis.yml
 Gemfile
+Gemfile.lock
 History.txt
 LICENSE
 Manifest.txt
 README.rdoc
 Rakefile
+appveyor.yml
 bin/kpeg
 examples/calculator/calculator.kpeg
 examples/calculator/calculator.rb
diff --git a/appveyor.yml b/appveyor.yml
new file mode 100644
index 0000000..1394018
--- /dev/null
+++ b/appveyor.yml
@@ -0,0 +1,35 @@
+version: '{build}'
+skip_tags: true
+clone_depth: 5
+build: off
+deploy: off
+
+init:
+  - mklink /d C:\git "C:\Program Files\Git"
+  - if %ruby_version%==_trunk (
+      appveyor DownloadFile https://ci.appveyor.com/api/projects/MSP-Greg/ruby-loco/artifacts/ruby_trunk.7z -FileName C:\ruby_trunk.7z &
+      7z x C:\ruby_trunk.7z -oC:\ruby_trunk )
+
+install:
+  - gem install hoe --no-document
+  - if "%ruby_version%" LSS "22" ( gem update minitest )
+
+test_script:
+- rake test
+on_finish:
+- ruby -v
+
+environment:
+  PATH: C:/ruby%ruby_version%/bin;C:/Program Files/7-Zip;C:/Program Files/AppVeyor/BuildAgent;C:/git/cmd;C:/Program Files (x86)/GNU/GnuPG/pub;C:/Windows/system32;C:\Windows;
+  matrix:
+  - ruby_version: 200
+  - ruby_version: 200-x64
+  - ruby_version: 21
+  - ruby_version: 21-x64
+  - ruby_version: 22
+  - ruby_version: 22-x64
+  - ruby_version: 23
+  - ruby_version: 23-x64
+  - ruby_version: 24
+  - ruby_version: 24-x64
+  - ruby_version: _trunk
diff --git a/lib/kpeg/format_parser.rb b/lib/kpeg/format_parser.rb
index 299e185..63c7ffe 100644
--- a/lib/kpeg/format_parser.rb
+++ b/lib/kpeg/format_parser.rb
@@ -914,7 +914,7 @@ def _dbl_not_quote
               break
             end
             _tmp = apply(:_dbl_escapes)
-            s = @result
+# warning unused s = @result
             unless _tmp
               self.pos = _save3
             end
@@ -924,7 +924,7 @@ def _dbl_not_quote
           break if _tmp
           self.pos = _save2
           _tmp = apply(:_dbl_seq)
-          s = @result
+# warning unused s = @result
           break if _tmp
           self.pos = _save2
           break
diff --git a/lib/kpeg/grammar.rb b/lib/kpeg/grammar.rb
index fab8ad2..b7532f7 100644
--- a/lib/kpeg/grammar.rb
+++ b/lib/kpeg/grammar.rb
@@ -129,6 +129,12 @@ def initialize(reg, opts=nil)
             end
           end
         end
+        # Windows - force to UTF-8 if reg contains a Unicode character property
+        # of the \p{**} style
+        if reg =~ /\{[LMNPSZC][c-u]?\}/ && RUBY_PLATFORM =~ /mswin|mingw/ &&
+            reg.encoding == Encoding::IBM437
+          reg.force_encoding('UTF-8')
+        end
 
         @regexp = Regexp.new(reg, flags, lang)
       else
diff --git a/test/test_kpeg.rb b/test/test_kpeg.rb
index a463ebd..fc8ed94 100644
--- a/test/test_kpeg.rb
+++ b/test/test_kpeg.rb
@@ -22,7 +22,7 @@ def test_str
     end
 
     assert_match KPeg.match("hello", gram), "hello"
-    assert_equal nil, KPeg.match("vador", gram)
+    assert_nil   KPeg.match("vador", gram)
   end
 
   def test_reg
@@ -48,7 +48,7 @@ def test_any
 
     assert_match KPeg.match("hello", gram), "hello"
     assert_match KPeg.match("chicken", gram), "chicken"
-    assert_equal nil, KPeg.match("vador", gram)
+    assert_nil   KPeg.match("vador", gram)
   end
 
   def test_maybe
@@ -78,7 +78,7 @@ def test_many
       assert_match sm, "run"
     end
 
-    assert_equal nil, KPeg.match("vador", gram)
+    assert_nil KPeg.match("vador", gram)
   end
 
   def test_kleene
@@ -124,9 +124,9 @@ def test_multiple
       assert_match sm, "run"
     end
 
-    assert_equal nil, KPeg.match("run", gram) 
-    assert_equal nil, KPeg.match("runrunrunrunrun", gram) 
-    assert_equal nil, KPeg.match("vador", gram) 
+    assert_nil KPeg.match("run", gram) 
+    assert_nil KPeg.match("runrunrunrunrun", gram) 
+    assert_nil KPeg.match("vador", gram) 
   end
 
   def test_seq
@@ -141,8 +141,8 @@ def test_seq
 
     assert_equal m.value, ["hello", ", world"]
 
-    assert_equal nil, KPeg.match("vador", gram)
-    assert_equal nil, KPeg.match("hello, vador", gram)
+    assert_nil KPeg.match("vador", gram)
+    assert_nil KPeg.match("hello, vador", gram)
   end
 
   def test_andp
@@ -346,7 +346,7 @@ def test_left_recursion
     parser = KPeg::Parser.new "hello", gram
     m = parser.parse
 
-    assert_equal nil, m
+    assert_nil m
   end
 
   def test_math_grammar
diff --git a/test/test_kpeg_code_generator.rb b/test/test_kpeg_code_generator.rb
index b6e5986..c040bf5 100644
--- a/test/test_kpeg_code_generator.rb
+++ b/test/test_kpeg_code_generator.rb
@@ -1079,7 +1079,7 @@ def _root
 
     code = cg.make("")
     assert code.parse
-    assert_equal nil, code.result
+    assert_nil code.result
   end
 
 
diff --git a/test/test_kpeg_string_escape.rb b/test/test_kpeg_string_escape.rb
index 6f9d977..c712e65 100644
--- a/test/test_kpeg_string_escape.rb
+++ b/test/test_kpeg_string_escape.rb
@@ -39,4 +39,3 @@ def parse(str, embed = false)
   end
 
 end
-