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 package implements selective applicative functors, which allow you to declare your effects statically, and select which to execute dynamically. See the paper on selective functors for more details.

This package provides a data type These a b which can hold a value of either type or values of each type. This is usually thought of as an "inclusive or" type (contrasting Either a b as "exclusive or") or as an "outer join" type (contrasting (a, b) as "inner join").

data These a b = This a | That b | These a b

Since version 1, this package was split into parts:

• https://hackage.haskell.org/package/semialign For Align and Zip type-classes.

• https://hackage.haskell.org/package/semialign-indexed For SemialignWithIndex class, providing ialignWith and izipWith

• https://hackage.haskell.org/package/these-lens For lens combinators.

• http://hackage.haskell.org/package/monad-chronicle For transformers variant of These.

This module allows tokens produced by skylighting-core to be rendered as Typst.

This package provides a means of generating tag files for Emacs and Vim.

This package (formerly binary-serialise-cbor) provides pure, efficient serialization of Haskell values directly into ByteStrings for storage or transmission purposes. By providing a set of type class instances, you can also serialise any custom data type you have as well.

The underlying binary format used is the 'Concise Binary Object Representation', or CBOR, specified in RFC 7049. As a result, serialised Haskell values have implicit structure outside of the Haskell program itself, meaning they can be inspected or analyzed without custom tools.

An implementation of the standard bijection between CBOR and JSON is provided by the https://hackage.haskell.org/package/cborg-json package. Also see https://hackage.haskell.org/package/cbor-tool for a convenient command-line utility for working with CBOR data.

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.

A UTF8 layer for Strings. The utf8-string package provides operations for encoding UTF8 strings to Word8 lists and back, and for reading and writing UTF8 without truncation.

This package makes it possible to define schemas for use when loading configuration files using the config-value format. These schemas can be used to process a configuration file into a Haskell value or to automatically generate documentation for the file format.

Haskell98 invariant functors (also known as exponential functors). For more information, see Edward Kmett's article Rotten Bananas.

Clear to write, read and edit Haskell DSL for HTML.

• Names are consistent, and do not conflict with base or are keywords (all have suffix -).

• Same combinator can be used for attributes and elements (e.g. style_).

This package provides a cross-platform implementation of system semaphores that abstracts over the `unix` and `Win32` libraries.

Contravariant functors for Haskell.

This package provides automatic formatting for Haskell files. Both a library and an executable.

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

Djot (<https://djot.net>) is a light markup language. This package provides a data structure to represent djot documents, a very fast parser, and functions to render a parsed document as HTML and as djot.

This library parses and dumps documents that are formatted according to RFC 4180, The common Format and MIME Type for Comma-Separated Values (CSV) Files. This format is used, among many other things, as a lingua franca for spreadsheets, and for certain web services.

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.

This Haskell library contains type definitions for Universally Unique Identifiers or UUIDs, and basic conversion functions.

This package provides datatypes to construct Free monads, Free monad transformers, and useful instances. In addition it provides the constructs to avoid quadratic complexity of left associative bind, as explained in:

• Janis Voigtlander, Asymptotic Improvement of Computations over Free Monads, MPC'08

This Haskell package defines typeclasses used for converting Haskell data types to and from HTTP API data.

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

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 a library to parse and render YAML documents.