The extra package

[Tags:bsd3, library, test]

A library of extra functions for the standard Haskell libraries. Most functions are simple additions, filling out missing functionality. A few functions are available in later versions of GHC, but this package makes them available back to GHC 7.2.

The module Extra documents all functions provided by this library. Modules such as Data.List.Extra provide extra functions over Data.List and also reexport Data.List. Users are recommended to replace Data.List imports with Data.List.Extra if they need the extra functionality.

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Properties

Versions	0.1, 0.2, 0.3, 0.3.1, 0.3.2, 0.4, 0.5, 0.5.1, 0.6, 0.7, 0.8, 1.0, 1.0.1, 1.1, 1.2, 1.3, 1.3.1, 1.4, 1.4.1, 1.4.2, 1.4.3, 1.4.4, 1.4.5, 1.4.6, 1.4.7, 1.4.8, 1.4.9, 1.4.10, 1.4.11, 1.4.12, 1.5
Change log	CHANGES.txt
Dependencies	base (>=4.4 && <5), clock (>=0.7), directory, filepath, process, time, unix [details]
License	BSD3
Copyright	Neil Mitchell 2014-2016
Author	Neil Mitchell <ndmitchell@gmail.com>
Maintainer	Neil Mitchell <ndmitchell@gmail.com>
Stability	Unknown
Category	Development
Home page	https://github.com/ndmitchell/extra#readme
Bug tracker	https://github.com/ndmitchell/extra/issues
Source repository	head: git clone https://github.com/ndmitchell/extra.git
Uploaded	Thu Jul 21 12:32:57 UTC 2016 by NeilMitchell
Distributions	Arch:1.5, Debian:1.4.2, FreeBSD:1.4.1, LTSHaskell:1.4.10, NixOS:1.5, Stackage:1.5, Tumbleweed:1.4.10
Downloads	16408 total (121 in the last 30 days)
Votes	0 []
Status	Docs uploaded by user Build status unknown [no reports yet]

Modules

Control
- Concurrent
  - Control.Concurrent.Extra
- Exception
  - Control.Exception.Extra
- Monad
  - Control.Monad.Extra
Data
- Either
  - Data.Either.Extra
- IORef
  - Data.IORef.Extra
- List
  - Data.List.Extra
- Tuple
  - Data.Tuple.Extra
- Typeable
  - Data.Typeable.Extra
- Version
  - Data.Version.Extra
Extra
Numeric
- Numeric.Extra
System
- Directory
  - System.Directory.Extra
- Environment
  - System.Environment.Extra
- IO
  - System.IO.Extra
- Info
  - System.Info.Extra
- Process
  - System.Process.Extra
- Time
  - System.Time.Extra

[Index]

Downloads

extra-1.5.tar.gz [browse] (Cabal source package)
Package description (included in the package)

Maintainer's Corner

For package maintainers and hackage trustees

edit package information

Readme for extra

Readme for extra-1.5

Extra

Control.Monad.Extra.concatMapM provides a monadic version of concatMap, in the same way that mapM is a monadic version of map.
Data.Tuple.Extra.fst3 provides a function to get the first element of a triple.
Control.Exception.Extra.retry provides a function that retries an IO action a number of times.
System.Environment.Extra.lookupEnv is a function available in GHC 7.6 and above. On GHC 7.6 and above this package reexports the version from System.Environment while on GHC 7.4 and below it defines an equivalent version.

Which functions?

When producing a library of extra functions I have been guided by a few principles. I encourage others with small useful utility functions contribute them here, perhaps as a temporary stop before proposing they join the standard libraries.

I have been using most of these functions in my packages - they have proved useful enough to be worth copying/pasting into each project.
The functions follow the spirit of the original Prelude/base libraries. I am happy to provide partial functions (e.g. fromRight), and functions which are specialisations of more generic functions (whenJust).
Most of the functions have trivial implementations. If a beginner couldn't write the function, it probably doesn't belong here.
I have defined only a few new data types or type aliases. It's a package for defining new utilities on existing types, not new types or concepts.

Base versions

The following GHC versions correspond to the following base library versions:

base 4.9 == GHC 8.0
base 4.8 == GHC 7.10
base 4.7 == GHC 7.8
base 4.6 == GHC 7.6
base 4.5 == GHC 7.4
base 4.4 == GHC 7.2

A more complete list can be found here.