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.

This package contains functions (like view or +=) which work on MonadReader, MonadWriter, and MonadState from the mtl package. This package is a part of the microlens family; see the readme on Github.

This library defines a propositional equality data type, shims Data.Type.Equality as well as possible for older GHC versions (< 7.8).

data a :~: b where
  Refl :: a :~: a

The module Data.Type.Equality.Hetero shims @code:~~: equality, and for compilers with PolyKinds.

This package provides Haskell bindings to your system's native wcwidth and a command line tool to examine the widths assigned by it. The command line tool can compile a width table to Haskell code that assigns widths to the Char type.

Utilities to parse, print, diff, and analyse data in CoNLL-U, a format used in linguistics to represent the syntactic annotation of sentences. See https://universaldependencies.org/format.html

Word8 library to be used with Data.ByteString.

The mockery package provides support functions for automated testing.

Types that are parametric on a functor are like Barbies that have an outfit for each role. This package provides the basic abstractions to work with them comfortably.

When you've caught all the exceptions that can be handled safely, this is what you're left with.

This package provides a mid-Level PostgreSQL client library, forked from ghc-mysql-simple.

This library provides functions to read, write and manipulate MIDI, WAVE and SoundFont2 multimedia files. It is written entirely in Haskell (without any FFI). It uses efficient parsing and building combinators for binary data stored in ByteStrings (based on the one in binary package).

This package provides a Haskell library for working with files and directories. It includes code for pattern matching, finding files, modifying file contents, and more.

This package provides a Storable instance for pairs and triples which should be binary compatible with C99 and C++. The only purpose of this package is to provide a standard location for this instance so that other packages needing this instance can play nicely together.

This library provides a wide array of (semi)groupoids and operations for working with them. A Semigroupoid is a Category without the requirement of identity arrows for every object in the category. A Category is any Semigroupoid for which the Yoneda lemma holds. Finally, to work with these weaker structures it is beneficial to have containers that can provide stronger guarantees about their contents, so versions of Traversable and Foldable that can be folded with just a Semigroup are added.

This library provides Comonads for Haskell.

This library provides functions available in later versions of base to a wider range of compilers, without requiring you to use CPP pragmas in your code. This package provides the same API as the base-compat library, but depends on compatibility packages (such as semigroups) to offer a wider support window than base-compat, which has no dependencies.

This Haskell package allows Haskell programs to access data storage systems like PostgreSQL, SQLite, and MariaDB in a type-safe way.

This package provides the ShortText type which is suitable for keeping many short strings in memory. This is similar to how ShortByteString relates to ByteString.

The main difference between Text and ShortText is that ShortText uses UTF-8 instead of UTF-16 internally and also doesn't support zero-copy slicing (thereby saving 2 words). Consequently, the memory footprint of a (boxed) ShortText value is 4 words (2 words when unboxed) plus the length of the UTF-8 encoded payload.

A cross-platform library with functions for adjusting code pages on Windows. On all other operating systems, the library does nothing.

This package is a Haskell library for the representation, parsing, and pretty-printing of GLSL 1.50 code.

This Haskell package provides a validator that can validate an email address string against RFC 5322.

This package provides a quasi-quoter for raw SQL for ghc-persistent.

This Haskell package provides a replacement for Data.Conduit.List, as well as a convenient Conduit module.

This package provides an API to Haddock, the documentation-generation tool for Haskell libraries.