The conduit package is a solution to the streaming data problem, allowing for production, transformation, and consumption of streams of data in constant memory. It is an alternative to lazy I/O which guarantees deterministic resource handling, and fits in the same general solution space as enumerator/iteratee and pipes.

The YAML 1.2 format provides a much richer data-model and feature-set than the JavaScript Object Notation format. However, sometimes it's desirable to ignore the extra capabilities and treat YAML as if it was merely a more convenient markup format for humans to write JSON data. To this end this module provides a compatibility layer atop ghc-hsyaml ,which allows decoding YAML documents in the more limited JSON data-model while also providing convenience by reusing ghc-aeson's FromJSON instances for decoding the YAML data into native Haskell data types.

The naive @foldl (\acc d -> acc * 10 + d) 0@ is expensive (quadratic!) for large @Integer@s. This package provides sub-quadratic implementation.

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 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.

Haskell library for parsing of ISO 8601 dates, originally from aeson.

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

This is a compatibility package as @Generically@ and @Generically1@ newtypes are available since @base-4.17@ in GHC.Generics'.

Most data types in the Haskell platform do not have Lift instances. This package provides orphan instances for containers, text, bytestring and vector.

This package provides a commutative semigroup is a semigroup where the order of arguments to mappend does not matter.

Lightweight pure data validation based on Applicative and Selective functors.

This package is for working with the native byte-ordering of the system.

This package provides a Conduit interface for the LZMA compression algorithm used in the .xz file format.

This package provides first class functional references. In addition to the usual operations of getting, setting and composition, plus integration with the state monad, lens families provide some unique features:

• Polymorphic updating

• Traversals

• Cast projection functions to read-only lenses

• Cast toList functions to read-only traversals

• Cast semantic editor combinators to modify-only traversals

For optimal first-class support use the lens-family package with rank 2/rank N polymorphism. Lens.Family.Clone allows for first-class support of lenses and traversals for those who require Haskell 98.

SDL_image is an image file loading library. It loads images as SDL surfaces, and supports the following formats: BMP, GIF, JPEG, LBM, PCX, PNG, PNM, TGA, TIFF, XCF, XPM, XV.

This library provides a utility function liftType, which accepts a type application argument and returns the Template Haskell Type representation of it.

ghc-citeproc parses Citation Style Language style files and uses them to generate a list of formatted citations and bibliography entries. For more information about CSL, see https://citationstyles.org/.

This package defines Counter type that can be safely modified concurrently from multiple threads. The type supports only few operations, namely read, write, cas (compare and swap), add, subtract and a few bitwise ones like or, and xor. Most common use case is having a shared counter that multiple threads increment. Another potential use case is lightweight locks.

vty is a terminal GUI library in the niche of ncurses, intended to be easy to use and to provide good support for common terminal types.

The ghc-lib-parser-ex package contains GHC API parse tree utilities.

Parse jira wiki text into an abstract syntax tree for easy transformation to other formats.

This package enables integration of terminal screen state in html pages.

This is only for use in developing libraries that should conform to the persistent interface, not for users of the persistent suite of database libraries.

This library makes it easy to implement monads with tricky control flow. This is useful for: writing web applications in a sequential style, programming games with a uniform interface for human and AI players and easy replay capabilities, implementing fast parser monads, designing monadic DSLs, etc.