This package provides a dependent sum is a generalization of a particular way of thinking about the Either type. Either a b can be thought of as a 2-tuple (tag, value), where the value of the tag determines the type of the value. In particular, either tag = Left and value :: a or tag = Right and value :: b. This package allows you to define your own dependent sum types by using your own "tag" types.

This package provides functions to marshal and unmarshal pandoc document types to and from Lua. . The values of most types are pushed to pandoc as "userdata" objects that wrap a stable pointer to the Haskell value; these objects come with methods to access and modify their properties. . Sequences are pushed as normal Lua tables, but are augmented with convenience functions.

This Haskell package is an abstract interface only. It provides a number of type clasess, but not an implementation. The type classes separate different levels of Par functionality. See the Control.Monad.Par.Class module for more details.

This package provides a pipe-based interface to the Aspell program (no dynamic linking required).

Wrappers and helpers to bridge Haskell and <https://www.lua.org/ Lua>. . It builds upon the /lua/ package, which allows bundling a Lua interpreter with a Haskell program.

This package provides a simple logging abstraction that allows multiple back-ends.

MissingH is a library of all sorts of utility functions for Haskell programmers. It is written in pure Haskell and thus should be extremely portable and easy to use.

Lifted-base exports IO operations from the base library lifted to any instance of MonadBase or MonadBaseControl. Note that not all modules from base are converted yet. The package includes a copy of the monad-peel test suite written by Anders Kaseorg.

This library provides support for parsing and generating BitTorrent files.

FoldMap lists are lists represented by their foldMap function. FoldMap lists have O(1) cons, snoc and append, just like DLists, but other operations might have favorable performance characteristics as well. These wild claims are still completely unverified though.

Get terminal window height and width without ncurses dependency.

This package provides Haskell bindings for libcmark, the reference parser for CommonMark, a fully specified variant of Markdown. It includes bundled libcmark sources, and does not require prior installation of the C library.

This package provides an implementation of the standard diff algorithm, and utilities for pretty printing.

This library provides higher order versions of Prelude classes to ease programming with polymorphic recursion and reduce UndecidableInstances.

This package contains the Control.Monad.Fail module providing the MonadFail class that became available in base-4.9.0.0 for older base package versions. This package turns into an empty package when used with GHC versions which already provide the Control.Monad.Fail module.

This library provides an easy way to define command line parsers.

The doctest program checks examples in source code comments. It is modeled after doctest for Python, see the Doctest website.

This Haskell package provides three useful generalizations:

class Functor f => FunctorWithIndex i f | f -> i where
  imap :: (i -> a -> b) -> f a -> f b

class Foldable f => FoldableWithIndex i f | f -> i where
  ifoldMap :: Monoid m => (i -> a -> m) -> f a -> m

class (FunctorWithIndex i t, FoldableWithIndex i t, Traversable t)
       => TraversableWithIndex i t | t -> i where
  itraverse :: Applicative f => (i -> a -> f b) -> t a -> f (t b)

The ghc-keys package provides similar functionality, but uses associated TypeFamilies instead of FunctionalDependencies.

doclayout is a pretty-printing library for laying out text documents, with several features not present in pretty-printing libraries designed for code. It was designed for use in Pandoc.

Manipulate identifiers and structurally non-complex pieces of text by delimiting word boundaries via a combination of whitespace, control-characters, and case-sensitivity.

Has support for common idioms like casing of programmatic variable names, taking, dropping, and splitting by word, and modifying the first character of a piece of text.

Caution: this library makes heavy use of the text library's internal loop optimisation framework. Since internal modules are not guaranteed to have a stable API there is potential for build breakage when the text dependency is upgraded. Consider yourself warned!

This library provides Control.Lens. The combinators in Control.Lens provide a highly generic toolbox for composing families of getters, folds, isomorphisms, traversals, setters and lenses and their indexed variants.

This library provides an efficient implementation of Int-indexed arrays (both mutable and immutable), with a powerful loop optimisation framework.

This package backports the Control.Monad.Except module from mtl (if using mtl-2.2.0.1 or earlier), which reexports the ExceptT monad transformer and the MonadError class.

This package should only be used if there is a need to use the Control.Monad.Except module specifically. If you just want the mtl class instances for ExceptT, use transformers-compat instead, since mtl-compat does nothing but reexport the instances from that package.

Note that unlike how mtl-2.2 or later works, the Control.Monad.Except module defined in this package exports all of ExceptT's monad class instances. Therefore, you may have to declare import Control.Monad.Except () at the top of your file to get all of the ExceptT instances in scope.

This package provides Haskell modules for accessing and manipulating fields of records.