Happy is a parser generator for Haskell. Given a grammar specification in BNF, Happy generates Haskell code to parse the grammar. Happy works in a similar way to the yacc tool for C.

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

This package provides Haskell bindings to the X11 graphics library. The bindings are a direct translation of the C bindings.

This package provides a newtype wrapper with FromJSON/ToJSON instances customisable via a phantom type parameter. The instances can be rendered to the original type using DerivingVia.

Haskell-Source with Extensions (HSE, haskell-src-exts) is an extension of the standard haskell-src package, and handles most registered syntactic extensions to Haskell. All extensions implemented in GHC are supported. Apart from these standard extensions, it also handles regular patterns as per the HaRP extension as well as HSX-style embedded XML syntax.

SDL_mixer is a sample multi-channel audio mixer library. It supports any number of simultaneously playing channels of 16 bit stereo audio, plus a single channel of music, mixed by the popular MikMod MOD, Timidity MIDI, Ogg Vorbis, and SMPEG MP3 libraries.

This package provides a set of helper programs necessary to build the Gtk2Hs suite of libraries. These tools include a modified c2hs binding tool that is used to generate FFI declarations, a tool to build a type hierarchy that mirrors the C type hierarchy of GObjects found in glib, and a generator for signal declarations that are used to call back from C to Haskell. These tools are not needed to actually run Gtk2Hs programs.

This library provides the natural numbers for Haskell.

This package provides utilities and combinators for parsing command line options in Haskell.

This library contains simple and easy-to-use primitives for I/O using streams.

Transformers provides functor and monad transformers, inspired by the paper "Functional Programming with Overloading and Higher-Order Polymorphism", by Mark P Jones, in Advanced School of Functional Programming, 1995 http://web.cecs.pdx.edu/~mpj/pubs/springschool.html.

This package contains:

• the monad transformer class (in Control.Monad.Trans.Class)

• concrete functor and monad transformers, each with associated operations and functions to lift operations associated with other transformers.

This package can be used on its own in portable Haskell code, in which case operations need to be manually lifted through transformer stacks (see Control.Monad.Trans.Class for some examples). Alternatively, it can be used with the non-portable monad classes in the mtl or monads-tf packages, which automatically lift operations introduced by monad transformers through other transformers.

This package provides vaults for Haskell. A vault is a persistent store for values of arbitrary types. It's like having first-class access to the storage space behind IORefs. The data structure is analogous to a bank vault, where you can access different bank boxes with different keys; hence the name. Also provided is a locker type, representing a store for a single element.

The config-ini Haskell library exports some simple monadic functions to ease the parsing of .ini-style configuration files, and to write and update them in an efficient diff-minimal way. This means that if you parse a file, update a single field, and reserialize, that file should differ only in the field we changed and that's it: field order, comments, and incidental whitespace will remain unchanged. The library aims to produce human-readable error messages when things go wrong.

This package implements utilities to perform atomic output so as to avoid the problem of partial intermediate files.

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.

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 implementation of the Wagner-Fischer dynamic programming algorithm to find the optimal edit script and cost between two sequences. The implementation in this package is specialised to sequences represented with Data.Vector but is otherwise agnostic to:

• The type of values in the vectors;

• The type representing edit operations; and

• The type representing the cost of operations.

This package provides Haskell bindings to bzlib and Conduit support for streaming compression and decompression.

This package provides ordered containers of intervals, with efficient search for all keys containing a point or overlapping an interval. See the example code on the home page for a quick introduction.

Atomically write to a file on POSIX-compliant systems while preserving permissions. mv is an atomic operation. This makes it simple to write to a file atomically just by using the mv operation. However, this will destroy the permissions on the original file. This library preserves permissions while atomically writing to a file.

This library provides tools for fast Unicode 12.1.0 normalization in Haskell (normalization forms C, KC, D, and KD).

This package provides an implementation of n-ary sums and n-ary products. The module Data.SOP is the main module of this library and contains more detailed documentation. The main use case of this package is to serve as the core of generics-sop.

This library provides mechanisms to efficiently run periodic, on-demand actions in Haskell.

This package provides access to platform dependent file locking APIs. There are alternative file locking packages:

• GHC.IO.Handle.Lock in base >= 4.10 is good enough for most use cases. However, uses only Handles so these locks cannot be used for intra-process locking.

• ghc-filelock doesn't support OFD locking.