模块，package和Haskell中的库有什么区别？

Question

What's the difference between module, package and library in Haskell?

From http://www.haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html
Prelude: a standard module imported by default into all Haskell modules.

From http://www.haskell.org/haskellwiki/Base_package
Base package: The base 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.

Thanks.

See also: What's the difference between a Python module and a Python package?

Answer 1

A module is a set of functions, types, classes, ... put together in a common namespace.

A library is a set of modules which makes sense to be together and that can be used in a program or another library.

A package is a unit of distribution that can contain a library or an executable or both. It's a way to share your code with the community.

Note that a library doesn't have to be in isolation in a package. That is, it's perfectly acceptable to have a library in your project that is used inside this project. The code is therefore seperated from the rest for clarity and maintainability. This is also a good way to isolate some general-purpose from your business logic code and this lib could eventually be extracted and shared between projects or with the community if needed.

Answer 2

Module: The individual file of a reusable code. The reusable code contains set of functions, classes etc. We can use these tested functions, classes etc. without reinventing the wheel in our code.

Package: A package is a directory which contains one or more modules.

Library: It is a directory where the packages are stored.