diff --git a/src/uuid.cpp b/src/uuid.cpp
index ebb6997..00e7331 100644
--- a/src/uuid.cpp
+++ b/src/uuid.cpp
@@ -8,8 +8,83 @@
 #include <CoreFoundation/CFUUID.h>
 #endif
 
+namespace 
+{
+   template <typename TChar>
+   constexpr inline unsigned char hex2char(TChar const ch)
+   {
+      if (ch >= static_cast<TChar>('0') && ch <= static_cast<TChar>('9'))
+         return ch - static_cast<TChar>('0');
+      if (ch >= static_cast<TChar>('a') && ch <= static_cast<TChar>('f'))
+         return 10 + ch - static_cast<TChar>('a');
+      if (ch >= static_cast<TChar>('A') && ch <= static_cast<TChar>('F'))
+         return 10 + ch - static_cast<TChar>('A');
+      return 0;
+   }
+   
+   template <typename TChar>
+   constexpr inline bool is_hex(TChar const ch)
+   {
+      return 
+         (ch >= static_cast<TChar>('0') && ch <= static_cast<TChar>('9')) ||
+         (ch >= static_cast<TChar>('a') && ch <= static_cast<TChar>('f')) ||
+         (ch >= static_cast<TChar>('A') && ch <= static_cast<TChar>('F'));
+   }
+
+   template <typename TChar>
+   constexpr inline unsigned char hexpair2char(TChar const a, TChar const b)
+   {
+      return (hex2char(a) << 4) | hex2char(b);
+   }
+}
+
 namespace uuids
 {
+   uuid::uuid(std::string const & str)
+   {
+      create(str.c_str(), str.size());
+   }
+
+   uuid::uuid(std::wstring const & str)
+   {
+      create(str.c_str(), str.size());
+   }
+
+   template <typename TChar>
+   void uuid::create(TChar const * const str, size_t const size)
+   {
+      TChar digit = 0;
+      bool firstdigit = true;
+      size_t index = 0;
+
+      for (size_t i = 0; i < size; ++i)
+      {
+         if (str[i] == static_cast<TChar>('-')) continue;
+
+         if (index >= 16 || !is_hex(str[i]))
+         {
+            std::fill(std::begin(data), std::end(data), 0);
+            return;
+         }
+
+         if (firstdigit)
+         {
+            digit = str[i];
+            firstdigit = false;
+         }
+         else
+         {
+            data[index++] = hexpair2char(digit, str[i]);
+            firstdigit = true;
+         }
+      }
+
+      if (index < 16)
+      {
+         std::fill(std::begin(data), std::end(data), 0);
+      }
+   }
+
    uuid make_uuid()
    {
 #ifdef _WIN32
diff --git a/src/uuid.h b/src/uuid.h
index 247d6ac..42b0cb2 100644
--- a/src/uuid.h
+++ b/src/uuid.h
@@ -4,6 +4,7 @@
 #include <sstream>
 #include <iomanip>
 #include <array>
+#include <string_view>
 
 namespace uuids
 {
@@ -59,6 +60,7 @@ namespace uuids
    // indicated by a bit pattern in octet 6, marked with M in xxxxxxxx-xxxx-Mxxx-xxxx-xxxxxxxxxxxx
    enum class version_type
    {
+      none = 0, // only possible for nil or invalid uuids
       time_based = 1,  // The time-based version specified in RFC 4122
       dce_security = 2,  // DCE Security version, with embedded POSIX UIDs.
       name_based_md5 = 3,  // The name-based version specified in RFS 4122 with MD5 hashing
@@ -91,10 +93,17 @@ namespace uuids
       typedef std::ptrdiff_t  difference_type;
 
    public:
-      constexpr uuid() {}
-      constexpr uuid(std::array<uint8_t, 16> const & bytes) :data{bytes} {}
+      constexpr explicit uuid() {}
+      constexpr explicit uuid(std::array<uint8_t, 16> const & bytes) :data{bytes} {}
+      explicit uuid(uint8_t const * const bytes)
+      {
+         std::copy(bytes, bytes + 16, std::begin(data));
+      }
 
-      variant_type variant() const noexcept
+      explicit uuid(std::string const & str);
+      explicit uuid(std::wstring const & str);
+
+      constexpr variant_type variant() const noexcept
       {
          if ((data[8] & 0x80) == 0x00)
             return variant_type::ncs;
@@ -106,7 +115,7 @@ namespace uuids
             return variant_type::future;
       }
 
-      version_type version() const
+      constexpr version_type version() const
       {
          if ((data[6] & 0xF0) == 0x10)
             return version_type::time_based;
@@ -119,14 +128,14 @@ namespace uuids
          else if ((data[6] & 0xF0) == 0x50)
             return version_type::name_based_sha1;
          else
-            throw guid_exception("invalid guid");
+            return version_type::none;
       }
 
-      std::size_t size() const noexcept { return 16; }
+      constexpr std::size_t size() const noexcept { return 16; }
 
-      bool is_nil() const noexcept
+      constexpr bool is_nil() const noexcept
       {
-         for (auto const e : data) if (e != 0) return false;
+         for (size_t i = 0; i < data.size(); ++i) if (data[i] != 0) return false;
          return true;
       }
 
@@ -174,6 +183,9 @@ namespace uuids
 
       friend bool operator==(uuid const & lhs, uuid const & rhs) noexcept;
 
+      template <typename TChar>
+      void create(TChar const * const str, size_t const size);
+
       template <class Elem, class Traits>
       friend std::basic_ostream<Elem, Traits> & operator<<(std::basic_ostream<Elem, Traits> &s, uuid const & id);
    };
diff --git a/test/test_win/stdafx.cpp b/test/test_win/stdafx.cpp
deleted file mode 100644
index b2a4568..0000000
Binary files a/test/test_win/stdafx.cpp and /dev/null differ
diff --git a/test/test_win/stdafx.h b/test/test_win/stdafx.h
deleted file mode 100644
index 94d4ed8..0000000
Binary files a/test/test_win/stdafx.h and /dev/null differ
diff --git a/test/test_win/targetver.h b/test/test_win/targetver.h
deleted file mode 100644
index 567cd34..0000000
Binary files a/test/test_win/targetver.h and /dev/null differ
diff --git a/test/test_win/test_win.cpp b/test/test_win/test_win.cpp
index 5354472..47cdec8 100644
Binary files a/test/test_win/test_win.cpp and b/test/test_win/test_win.cpp differ
diff --git a/test/test_win/test_win.vcxproj b/test/test_win/test_win.vcxproj
index f0db909..1fe8cc1 100644
--- a/test/test_win/test_win.vcxproj
+++ b/test/test_win/test_win.vcxproj
@@ -89,6 +89,7 @@
       <Optimization>Disabled</Optimization>
       <SDLCheck>true</SDLCheck>
       <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <LanguageStandard>stdcpplatest</LanguageStandard>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -102,6 +103,7 @@
       <Optimization>Disabled</Optimization>
       <SDLCheck>true</SDLCheck>
       <PreprocessorDefinitions>_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <LanguageStandard>stdcpplatest</LanguageStandard>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -117,6 +119,7 @@
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <SDLCheck>true</SDLCheck>
       <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <LanguageStandard>stdcpplatest</LanguageStandard>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -134,6 +137,7 @@
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <SDLCheck>true</SDLCheck>
       <PreprocessorDefinitions>NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <LanguageStandard>stdcpplatest</LanguageStandard>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -144,7 +148,6 @@
   </ItemDefinitionGroup>
   <ItemGroup>
     <ClInclude Include="..\..\src\uuid.h" />
-    <ClInclude Include="targetver.h" />
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="..\..\src\uuid.cpp" />
diff --git a/test/test_win/test_win.vcxproj.filters b/test/test_win/test_win.vcxproj.filters
index 7adf8d3..cc90555 100644
--- a/test/test_win/test_win.vcxproj.filters
+++ b/test/test_win/test_win.vcxproj.filters
@@ -15,9 +15,6 @@
     </Filter>
   </ItemGroup>
   <ItemGroup>
-    <ClInclude Include="targetver.h">
-      <Filter>Header Files</Filter>
-    </ClInclude>
     <ClInclude Include="..\..\src\uuid.h">
       <Filter>Header Files</Filter>
     </ClInclude>
diff --git a/test/test_win/test_win.vcxproj.user b/test/test_win/test_win.vcxproj.user
new file mode 100644
index 0000000..baf2417
--- /dev/null
+++ b/test/test_win/test_win.vcxproj.user
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <ShowAllFiles>false</ShowAllFiles>
+  </PropertyGroup>
+</Project>
\ No newline at end of file