diff --git a/.gitignore b/.gitignore
index 528610a..4532471 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
+**/uuids
+
 .vscode/.browse.*
 nimsuggest.log
 
diff --git a/uuids/urandom.nim b/src/urandom.nim
similarity index 93%
rename from uuids/urandom.nim
rename to src/urandom.nim
index 6078de4..3666214 100644
--- a/uuids/urandom.nim
+++ b/src/urandom.nim
@@ -16,16 +16,16 @@ when defined(windows):
     proc CryptAcquireContext(
       phProv: ptr HCRYPTPROV, pszContainer: WideCString,
       pszProvider: WideCString, dwProvType: DWORD, dwFlags: DWORD
-    ): WINBOOL {.importc: "CryptAcquireContextW".}
+    ): WinBool {.importc: "CryptAcquireContextW".}
   else:
     proc CryptAcquireContext(
       phProv: ptr HCRYPTPROV, pszContainer: cstring, pszProvider: cstring,
       dwProvType: DWORD, dwFlags: DWORD
-    ): WINBOOL {.importc: "CryptAcquireContextA".}
+    ): WinBool {.importc: "CryptAcquireContextA".}
 
   proc CryptGenRandom(
     hProv: HCRYPTPROV, dwLen: DWORD, pbBuffer: pointer
-  ): WINBOOL {.importc: "CryptGenRandom".}
+  ): WinBool {.importc: "CryptGenRandom".}
 
   {.pop.}
 
diff --git a/uuids.nim b/src/uuids.nim
similarity index 95%
rename from uuids.nim
rename to src/uuids.nim
index b44ede2..4a1f034 100644
--- a/uuids.nim
+++ b/src/uuids.nim
@@ -1,6 +1,6 @@
 import strutils, hashes
 import isaac
-import uuids/urandom
+import urandom
 
 type
   UUID* = object
@@ -10,17 +10,16 @@ type
 
 template toHex(s: string, start: Natural,
                x: BiggestInt, len: Positive) =
-  const HexChars = ['0', '1', '2', '3', '4', '5', '6', '7', '8',
-                    '9', 'a', 'b', 'c', 'd', 'e', 'f']
+  const HexChars = "0123456789abcdef"
   var n = x
   for j in countdown(len - 1, 0):
-    s[start + j] = HexChars[int(n and 0xF)]
+    s[start + j] = HexChars[n and 0xF]
     n = n shr 4
     # handle negative overflow
     if n == 0 and x < 0: n = -1
 
 proc uuidsParseHexInt(s: string, maxLen: int): int64 =
-  if s.len == 0:
+  if s.isNil or s.len == 0:
     raise newException(ValueError, "UUID part is empty")
   if s.len > maxLen or s.len > sizeof(result) * 2:
     raise newException(ValueError, "UUID part is longer than expected")
diff --git a/uuids.nimble b/uuids.nimble
index ccc6e86..7a5c79a 100644
--- a/uuids.nimble
+++ b/uuids.nimble
@@ -1,9 +1,10 @@
 [Package]
 name: "uuids"
-version: "0.1.11"
+version: "0.1.7"
 author: "Xored Software, Inc."
 description: "UUID library"
 license: "MIT"
+srcDir: "src"
 
 [Deps]
-requires: "isaac >= 0.1.3"
+requires: "isaac >= 0.1.2"