A simple directory-like tree datatype, with useful IO functions
|Version on this page:||0.12.0|
|LTS Haskell 20.25:||0.12.1|
|Stackage Nightly 2023-06-10:||0.12.1|
|Latest on Hackage:||0.12.1|
Module documentation for 0.12.0
A simple directory-like tree datatype, with useful IO functions and Foldable and Traversable instance
Provides a simple data structure mirroring a directory tree on the filesystem, as well as useful functions for reading and writing file and directory structures in the IO monad.
Importing the library and optional (useful) Foldable and Traverable libraries:
import System.Directory.Tree import qualified Data.Foldable as F import qualified Data.Traversable as T
Write a hand-made directory tree of textfiles (strings) to the disk. Simulates creating a new user Tux's home directory on a unix machine:
writeDirectory$ "/home" :/ Dir "Tux" [File "README" "Welcome!"]
"read" a directory by opening all the files at a filepath with readFile, returning an 'AnchoredDirTree String' (d2). Then check for any IO failures:
do (base :/ d2) <- readDirectory "../parent_dir/dir2/" let failed = anyFailed d2 if failed then ...
Use Foldable instance function to concat a directory
dir of text files into a
single file under the same directory:
do (b :/ dt) <- readDirectory dir let f = F.concat dt return$ b :/ File "ALL_TEXT" f
Open all the files in the current directory as lazy bytestrings, ignoring the base path in Anchored wrapper:
import qualified Data.ByteString.Lazy as B do (_ :/ dTree) <- readDirectoryWith B.readFile "./"
This version also offers an experimental function
readDirectoryWithL that does
lazy directory IO, allowing you to treat the returned
DirTree as if it were a
normal lazily-generated data structure.
For example, the following does only the amount of IO necessary to list the file names of the children of the root directory, similar to "ls /":
do d <- readDirectoryWithL readFile "/" mapM_ (putStrLn . name) $ contents $ free d
Any ideas or suggestions for improvements are most welcome :-)
CHANGES: from 0.11
add test suite to cabal file
removeNonexistent(thanks to dmwit for patch)