Awesome
FilePath ![Hackage version](https://img.shields.io/hackage/v/filepath.svg?label=Hackage)
The filepath
package provides functionality for manipulating FilePath
values, and is shipped with GHC.
It provides two variants for filepaths:
- legacy filepaths:
type FilePath = String
- operating system abstracted filepaths (
OsPath
): internally unpinnedShortByteString
(platform-dependent encoding)
It is recommended to use OsPath
when possible, because it is more correct.
For each variant there are three main modules:
System.FilePath.Posix
/System.OsPath.Posix
manipulates POSIX/Linux styleFilePath
values (with/
as the path separator).System.FilePath.Windows
/System.OsPath.Windows
manipulates Windows styleFilePath
values (with either\
or/
as the path separator, and deals with drives).System.FilePath
/System.OsPath
for dealing with current platform-specific filepaths
All three modules provide the same API, and the same documentation (calling out differences in the different variants).
System.OsString
is like System.OsPath
, but more general purpose. Refer to the documentation of
those modules for more information.
What is a FilePath
?
In Haskell, the legacy definition (used in base
and Prelude) is type FilePath = String
,
where a Haskell String
is a list of Unicode code points.
The new definition is (simplified) newtype OsPath = AFP ShortByteString
, where
ShortByteString
is an unpinned byte array and follows syscall conventions, preserving the encoding.
On unix, filenames don't have a predefined encoding as per the
POSIX specification
and are passed as char[]
to syscalls.
On windows (at least the API used by Win32
) filepaths are UTF-16LE strings.
You are encouraged to use OsPath
whenever possible, because it is more correct.
Also note that this is a low-level library and it makes no attempt at providing a more type safe variant for filepaths (e.g. by distinguishing between absolute and relative paths) and ensures no invariants (such as filepath validity).
For such libraries, check out the following: