diff --git a/build/Helpers.lua b/build/Helpers.lua
index 0c86e0f0..3d34ac83 100644
--- a/build/Helpers.lua
+++ b/build/Helpers.lua
@@ -24,18 +24,6 @@ gcc_buildflags = { "-std=c++11 -fpermissive" }
 
 msvc_cpp_defines = { }
 
-function os.is_osx()
-  return os.is("macosx")
-end
-
-function os.is_windows()
-  return os.is("windows")
-end
-
-function os.is_linux()
-  return os.is("linux")
-end
-
 function string.starts(str, start)
    return string.sub(str, 1, string.len(start)) == start
 end
@@ -79,7 +67,7 @@ function SetupManagedProject()
   language "C#"
   location (path.join(builddir, "projects"))
 
-  if not os.is_osx() then
+  if not os.is("macosx") then
     local c = configuration { "vs*" }
       location "."
     configuration(c)
diff --git a/build/Parser.lua b/build/Parser.lua
index 6f0c138c..e8fc9a1c 100644
--- a/build/Parser.lua
+++ b/build/Parser.lua
@@ -11,7 +11,7 @@ function SetupCSharpParser()
 end
 
 function SetupParser()
-  if string.match(action, "vs*") and os.is_windows() then
+  if string.match(action, "vs*") and os.is("windows") then
     SetupCLIParser()
   else
     SetupCSharpParser()
diff --git a/build/Tests.lua b/build/Tests.lua
index a119b99e..47822968 100644
--- a/build/Tests.lua
+++ b/build/Tests.lua
@@ -76,7 +76,7 @@ function SetupTestGeneratorBuildEvent(name)
 end
 
 function SetupTestNativeProject(name, depends)
-  if string.starts(action, "vs") and not os.is_windows() then
+  if string.starts(action, "vs") and not os.is("windows") then
     return
   end
 
@@ -141,7 +141,7 @@ function SetupTestProjectsCSharp(name, depends)
 end
 
 function SetupTestProjectsCLI(name, extraFiles)
-  if not os.is_windows() then
+  if not os.is("windows") then
     return
   end
 
diff --git a/build/scripts/LLVM.lua b/build/scripts/LLVM.lua
index 51c2b237..3e8c68c6 100644
--- a/build/scripts/LLVM.lua
+++ b/build/scripts/LLVM.lua
@@ -154,7 +154,7 @@ end
 function cmake(gen, conf, builddir, options)
 	local cwd = os.getcwd()
 	os.chdir(builddir)
-	local cmake = os.is_osx() and "/Applications/CMake.app/Contents/bin/cmake"
+	local cmake = os.is("macosx") and "/Applications/CMake.app/Contents/bin/cmake"
 		or "cmake"
 	local cmd = cmake .. " -G " .. '"' .. gen .. '"'
  		.. ' -DLLVM_BUILD_TOOLS=false '
diff --git a/src/CppParser/Bindings/premake5.lua b/src/CppParser/Bindings/premake5.lua
index 83e90aa1..0c3200f2 100644
--- a/src/CppParser/Bindings/premake5.lua
+++ b/src/CppParser/Bindings/premake5.lua
@@ -15,9 +15,9 @@ project "CppSharp.Parser.CSharp"
 
   links { "CppSharp.Runtime" }
 
-  if os.is_windows() then
+  if os.is("windows") then
       files { "CSharp/i686-pc-win32-msvc/**.cs" }
-  elseif os.is_osx() then
+  elseif os.is("macosx") then
       local file = io.popen("lipo -info `which mono`")
       local output = file:read('*all')
       if string.find(output, "x86_64") then  
@@ -26,7 +26,7 @@ project "CppSharp.Parser.CSharp"
         files { "CSharp/i686-apple-darwin12.4.0/**.cs" }
       end
 
-  elseif os.is_linux() then
+  elseif os.is("linux") then
       files { "CSharp/x86_64-linux-gnu/**.cs" }
   else
       print "Unknown architecture"
@@ -34,7 +34,7 @@ project "CppSharp.Parser.CSharp"
 
   configuration ""
 
-if string.starts(action, "vs") and os.is_windows() then
+if string.starts(action, "vs") and os.is("windows") then
 
   project "CppSharp.Parser.CLI"
     
diff --git a/src/CppParser/premake5.lua b/src/CppParser/premake5.lua
index b642176f..b0b438e4 100644
--- a/src/CppParser/premake5.lua
+++ b/src/CppParser/premake5.lua
@@ -6,7 +6,7 @@ clang_msvc_flags =
   "/wd4141", -- 'inline' : used more than once
 }
 
-if not (string.starts(action, "vs") and not os.is_windows()) then
+if not (string.starts(action, "vs") and not os.is("windows")) then
 
 project "CppSharp.CppParser"