GHC 7.4 gave us the ability to talk about ConstraintKinds. They stopped crashing the compiler in GHC 7.6. This package provides a vocabulary for working with them.

This library implements a technique to catch all exceptions raised within an enclosed computation, while remaining responsive to (external) asynchronous exceptions.

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

This Haskell library provides a type class for the error function, erf, and related functions. Instances for Float and Double.

This package provides modules containing facilities for manipulating Haskell source code using Template Haskell. See http://www.haskell.org/haskellwiki/Template_Haskell for more information.

This package contains the C sources of LPeg, as well as some tiny Haskell helper to load the package. . <http://www.inf.puc-rio.br/~roberto/lpeg/>

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.

Derive instances of Arbitrary for QuickCheck, with various options to customize implementations.

Automating the arbitrary boilerplate also ensures that when a type changes to have more or fewer constructors, then the generator either fixes itself to generate that new case (when using the uniform distribution) or causes a compilation error so you remember to fix it (when using an explicit distribution).

This package also offers a simple (optional) strategy to ensure termination for recursive types: make Test.QuickCheck.Gen's size parameter decrease at every recursive call; when it reaches zero, sample directly from a trivially terminating generator given explicitly (genericArbitraryRec and withBaseCase) or implicitly (genericArbitrary').

This library provides the natural numbers for Haskell.

This package normalizes variations in the interface for inspecting datatype information via Template Haskell so that packages and support a single, easier to use informational datatype while supporting many versions of Template Haskell.

This package provides basic types for representing XML documents.

This package provides a simple XML library for Haskell.

This library provides the natural numbers for Haskell.

IWlib is a thin Haskell binding to the iw C library. It provides information about the current wireless network connections, and adapters on supported systems.

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 is an enhancement of the Text.Regex library. It wraps the PCRE C library providing Perl-compatible regular expressions.

This package provides tools to parse and produce literals efficiently from strict or lazy bytestrings.

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_).

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.

Utilities for dealing with IEEE floating point numbers, ported from the Tango math library; approximate and exact equality comparisons for general types.

This library provides bindings for the Dot language used by the Graphviz suite of programs for visualising graphs, as well as functions to call those programs. Main features of the graphviz library include:

1. Almost complete coverage of all Graphviz attributes and syntax

2. Support for specifying clusters

3. The ability to use a custom node type

4. Functions for running a Graphviz layout tool with all specified output types

5. Generate and parse Dot code with two options: strict and liberal

6. Functions to convert FGL graphs and other graph-like data structures

7. Round-trip support for passing an FGL graph through Graphviz to augment node and edge labels with positional information, etc.

This package provides a writer monad for multi-line string literals.

This library uses GHC.Generics to derive efficient optics (traversals, lenses and prisms) for algebraic data types in a type-directed way, with a focus on good type inference and error messages when possible. This package is the shared internal logic of the generic-lens and generic-optics libraries.

Turtle is a reimplementation of the Unix command line environment in Haskell so that you can use Haskell as both a shell and a scripting language. Features include:

• Batteries included: Command an extended suite of predefined utilities.

• Interoperability: You can still run external shell commands.

• Portability: Works on Windows, OS X, and Linux.

• Exception safety: Safely acquire and release resources.

• Streaming: Transform or fold command output in constant space.

• Patterns: Use typed regular expressions that can parse structured values.

• Formatting: Type-safe printf-style text formatting.

• Modern: Supports text and system-filepath.

Read "Turtle.Tutorial" for a detailed tutorial or "Turtle.Prelude" for a quick-start guide. Turtle is designed to be beginner-friendly, but as a result lacks certain features, like tracing commands. If you feel comfortable using turtle then you should also check out the Shelly library which provides similar functionality.