fs-api

The fs-api package provides an abstract interface to filesystems. The abstract interface is a datatype called HasFS, which is parameterised over a monad m that filesystem operations run in, and the type of file handles h. removeFile is an example of a filesystem operation in this interface.

data HasFS m h = HasFS {
    {- omitted -}
    -- | Remove the file (which must exist)
  , removeFile               :: HasCallStack => FsPath -> m ()
    {- omitted -}
  }

Code that is written using this interface can be run against any implementation of a file system. The System.FS.IO module provides a function for initialising a HasFS interface for the real filesystem.

ioHasFS :: (MonadIO m, PrimState IO ~ PrimState m) => MountPoint -> HasFS m HandleIO

Note that ioHasFS requires some context in the form of a MountPoint: the base directory in which the filesystem operations should be run.