The not so great automatic Haskell licensor

Licensor is a program that generates a report of the dependencies and transitive dependencies of a Haskell project and their licenses.

Description

Choosing a license for a software project or determining whether a particular dependency can be added to a project can be projects themselves. Unless starting from scratch, programmers should consider the licenses of the dependencies and transitive dependencies of their projects to make informed decisions and avoid license compatibility issues.

Of course, this is just a starting point. "Beyond (...) general observations, it is difficult, if not impossible, to provide precise guidance about what licenses may or may not be compatible with each other. (...) Programmers who are considering combining code governed by two or more different licenses should proceed cautiously" (Andrew M. St. Laurent).

Disclaimer

Licensor is not a lawyer and does not provide legal advice.

For more information about licenses and license compatibility issues, read the text of the licenses or consult with a lawyer before making any decision.

Related programs

Licensor is not the only license compatibility helper for Haskell:

• Licensor uses a Cabal library and Stack program approach for detecting licenses and listing dependencies, respectively. For a Cabal library and program approach, consider using the cabal-dependency-licenses program.

Installation and usage

To install Licensor, use Cabal:

$ cabal update && cabal install licensor

Then, run the licensor executable inside a Haskell project:

$ licensor

To see the license report for Licensor, clone the repository:

$ git clone https://github.com/jpvillaisaza/licensor

And run licensor inside the project:

$ cd licensor/ && licensor

Or build and run licensor inside the project:

$ cd licensor/ && stack build --exec licensor

For more information, run licensor --help:

licensor 0.2.0

licensor [OPTIONS]

Common flags:
  -? --help             Display help message
  -V --version          Print version information
     --numeric-version  Print just the version number

Notes

Dependencies

Licensor uses the Stack program to list dependencies for a Haskell project. A future enhancement could be to use the Stack library.

Licenses and license detection

Licensor uses the Cabal library to detect the license of a Haskell project and its dependencies (including transitive dependencies). To do so, it uses the license field in the package description. A future enhancement could be to use both the license and licence file fields in the package description.

Cabal provides an enumeration of common open source and free software licenses. These are the licenses that appear in the reports generated by Licensor:

License	Description
GPL	GNU General Public License
AGPL	GNU Affero General Public License
LGPL	GNU Lesser General Public License
BSD2	BSD 2-Clause License
BSD3	BSD 3-Clause License
BSD4	BSD 4-Clause License
MIT	MIT License
ISC	ISC License
MPL	Mozilla Public License
Apache	Apache License
PublicDomain	Public domain
AllRightsReserved	All rights reserved
UnspecifiedLicense	Unspecified license (All rights reserved)
OtherLicense	Other license
UnknownLicense	Unknown license

Contribution guidelines

Feel free to create issues for reporting bugs and suggesting enhancements, or to fork the repository and open a pull request.

License

Licensor is licensed under the MIT License. See LICENSE.md.

License report

Licensor (0.2.0) depends on the following libraries:

Library	License
base	BSD3
bytestring	BSD3
Cabal	BSD3
cmdargs	BSD3
containers	BSD3
directory	BSD3
http-conduit	BSD3
process	BSD3

And the following licenses (including transitive dependencies):

License	Number of libraries
BSD3	68
MIT	7

(Tested with Licensor 0.2.0, Stack 1.2.0, and LTS 7.0.)

Additional resources

• Choose a License
• License compatibility
• Understanding open source and free software licensing (Andrew M. St. Laurent)