filepath-bytestring: Library for manipulating RawFilePaths in a cross platform way.

[ bsd3, library, system ] [ Propose Tags ]

This package provides functionality for manipulating RawFilePath values. It can be used as a drop in replacement for the filepath library to get the benefits of using ByteStrings. It provides three modules:

All three modules provide the same API, and the same documentation (calling out differences in the different variants).

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Dependencies base (>=4 && <4.16), bytestring, unix, utf8-string [details]
License BSD-3-Clause
Copyright Neil Mitchell 2005-2019 Joey Hess 2019-2021
Author Neil Mitchell <>
Maintainer Joey Hess <>
Category System
Source repo head: git clone git://
Uploaded by JoeyHess at 2021-08-11T16:20:43Z
Distributions Arch:, Fedora:, LTSHaskell:, NixOS:, Stackage:, openSUSE:
Downloads 3944 total (188 in the last 30 days)
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Status Hackage Matrix CI
Docs available [build log]
Last success reported on 2021-08-11 [all 1 reports]


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FilePath Hackage version Linux build status Windows build status

The filepath-bytestring package provides functionality for manipulating RawFilePath values (ByteStrings). Its interface is equivilant to the filepath package. It provides three modules:

All three modules provide the same API, and the same documentation (calling out differences in the different variants).

Developer notes

This package's version should be the same as the filepath it's derived from, with an added revision number.

Most of the code is in System/FilePath/Internal.hs which is #include'd into both System/FilePath/Posix.hs and System/FilePath/Windows.hs with the IS_WINDOWS CPP define set to either True or False. This Internal module is a bit weird in that it isn't really a Haskell module, but is more an include file.

The library has extensive doc tests. Anything starting with -- > is transformed into a doc test as a predicate that must evaluate to True. These tests follow a few rules:

  • Tests prefixed with Windows: or Posix: are only tested against that specific implementation - otherwise tests are run against both implementations.
  • Any single letter variable, e.g. x, is considered universal quantification, and is checked with QuickCheck.
  • If Valid x => appears at the start of a doc test, that means the property will only be tested with x passing the isValid predicate.

Also, all exported functions are quickchecked against the ones from filepath to make sure thay generate equivilant results.

The tests can be generated by Generate.hs in the root of the repo, and will be placed in tests/TestGen.hs. The TestGen.hs file is checked into the repo, and the CI scripts check that TestGen.hs is in sync with what would be generated a fresh - if you don't regenerate TestGen.hs the CI will fail.

The .ghci file is set up to allow you to type ghci to open the library, then :go will regenerate the tests and run them.