The libraries are divided into several packages. The available package are:

base

This package contains the Prelude and its support libraries, and a large collection of useful libraries ranging from data structures to parsing combinators and debugging utilities.

haskell98

This package contains the Haskell 98 Standard and FFI Standard Libraries. For more information on the Haskell 98 Standard Libraries, please see the Haskell 98 Library Report, here: http://www.haskell.org/onlinelibrary/.

haskell-src

Facilities for manipulating Haskell source code: an abstract syntax, lexer, parser and pretty-printer.

network

Networking-related facilities.

parsec

A monadic parser combinator library, written by Daan Leijen. Parsec is designed from scratch as an industrial-strength parser library. It is simple, safe, well documented, has extensive libraries and good error messages, and is also fast. More documentation can be found on: http://www.cs.uu.nl/~daan/parsec.html

QuickCheck

A library for testing Haskell programs automatically. The programmer provides a specification of the program, in the form of properties which functions should satisfy, and QuickCheck then tests that the properties hold in a large number of randomly generated cases. Specifications are expressed in Haskell, using combinators defined in the QuickCheck library. QuickCheck provides combinators to define properties, observe the distribution of test data, and define test data generators. For more information, please see: http://www.math.chalmers.se/~rjmh/QuickCheck/.

readline

An interface to the GNU readline library. More information on readline can be found at http://www.gnu.org/directory/readline.html.

unix

POSIX functionality.

Implementation-specific notes:

GHC/GHCi

Most of the time, all the packages are available without the need to use any additional command-line options. The only time when this is not the case is when linking a program on the command line, without using the --make option: in this case you must list all the packages to link to by adding the -package P flag (where P is the package name) to the command line for each package. See the User's Guide (../users_guide/users-guide.html) for more details.

Hugs

Hugs provides almost all of the modules in the the above packages (with exceptions listed on the Hugs 98 libraries status page (http://cvs.haskell.org/Hugs/pages/libstatus.html). All those modules are always available, as a single hierarchy; Hugs does not use the package subdivision.

Nhc98

Nhc98 provides many of the modules in the the above packages (see the Nhc98 libraries page (http://www.haskell.org/nhc98/libraries.html) for a more details). The modules of the haskell98 package are available without the need to use any additional compile-time options. To use modules from some other package P with Nhc98, add the compile-time option -package P.