diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,25 @@
+The following license covers this documentation, and the source code, except
+where otherwise indicated.
+
+Copyright 2009, Michael Snoyman. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS "AS IS" AND ANY EXPRESS OR
+IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
+OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Setup.lhs b/Setup.lhs
new file mode 100644
--- /dev/null
+++ b/Setup.lhs
@@ -0,0 +1,7 @@
+#!/usr/bin/env runhaskell
+
+> module Main where
+> import Distribution.Simple
+
+> main :: IO ()
+> main = defaultMain
diff --git a/Web/PathPieces.hs b/Web/PathPieces.hs
new file mode 100644
--- /dev/null
+++ b/Web/PathPieces.hs
@@ -0,0 +1,55 @@
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE TypeSynonymInstances #-}
+module Web.PathPieces
+    ( SinglePiece (..)
+    , MultiPiece (..)
+    ) where
+
+import Data.Int (Int64)
+import qualified Data.Text as S
+import qualified Data.Text.Lazy as L
+import qualified Data.Text.Read
+
+class SinglePiece s where
+    fromSinglePiece :: S.Text -> Maybe s
+    toSinglePiece :: s -> S.Text
+instance SinglePiece String where
+    fromSinglePiece s = if S.null s then Nothing else Just (S.unpack s)
+    toSinglePiece = S.pack
+instance SinglePiece S.Text where
+    fromSinglePiece s = if S.null s then Nothing else Just s
+    toSinglePiece = id
+instance SinglePiece L.Text where
+    fromSinglePiece s = if S.null s then Nothing else Just (L.fromChunks [s])
+    toSinglePiece = S.concat . L.toChunks
+instance SinglePiece Integer where
+    fromSinglePiece s =
+        case Data.Text.Read.decimal s of
+            Right (i, _) -> Just i
+            Left _ -> Nothing
+    toSinglePiece = S.pack . show
+instance SinglePiece Int where
+    fromSinglePiece s =
+        case Data.Text.Read.decimal s of
+            Right (i, _) -> Just i
+            Left _ -> Nothing
+    toSinglePiece = S.pack . show
+instance SinglePiece Int64 where
+    fromSinglePiece s =
+        case Data.Text.Read.decimal s of
+            Right (i, _) -> Just i
+            Left _ -> Nothing
+    toSinglePiece = S.pack . show
+
+class MultiPiece s where
+    fromMultiPiece :: [S.Text] -> Maybe s
+    toMultiPiece :: s -> [S.Text]
+instance MultiPiece [String] where
+    fromMultiPiece = Just . map S.unpack
+    toMultiPiece = map S.pack
+instance MultiPiece [S.Text] where
+    fromMultiPiece = Just
+    toMultiPiece = id
+instance MultiPiece [L.Text] where
+    fromMultiPiece = Just . map (L.fromChunks . return)
+    toMultiPiece = map $ S.concat . L.toChunks
diff --git a/path-pieces.cabal b/path-pieces.cabal
new file mode 100644
--- /dev/null
+++ b/path-pieces.cabal
@@ -0,0 +1,22 @@
+name:            path-pieces
+version:         0.0.0
+license:         BSD3
+license-file:    LICENSE
+author:          Michael Snoyman <michael@snoyman.com>
+maintainer:      Michael Snoyman <michael@snoyman.com>
+synopsis:        Components of paths.
+category:        Web, Yesod
+stability:       unstable
+cabal-version:   >= 1.6
+build-type:      Simple
+homepage:        http://github.com/snoyberg/path-pieces
+
+library
+    build-depends:   base             >= 4       && < 5
+                   , text             >= 0.5     && < 0.12
+    exposed-modules: Web.PathPieces
+    ghc-options:     -Wall
+
+source-repository head
+  type:     git
+  location: git://github.com/snoyberg/path-pieces.git