nixos-types-1.0: Data types representing the Nix language




Known licenses in Nix expressions are represented using the attributes defined in pkgs/lib/licenses.nix, and unknown licenses are represented as a literal string.



data License Source

The representation for licenses used in Nix derivations. Known licenses are Nix expressions -- such as stdenv.lib.licenses.bsd3 --, so their exact "name" is not generally known, because the path to stdenv depends on the context defined in the expression. In Cabal expressions, for example, the BSD3 license would have to be referred to as self.stdenv.lib.licenses.bsd3. Other expressions, however, use different paths to the licenses record.. Because of this station, this library cannot provide an abstract data type that encompasses all known licenses. Instead, the License type just distinguishes references to known and unknown licenses. The difference between the two is in the way they are pretty-printed:

 > putStrLn (display (Known "stdenv.lib.license.gpl2"))

 > putStrLn (display (Unknown (Just "GPL")))

 > putStrLn (display (Unknown Nothing))

Note that the Text instance definition provides pretty-printing, but no parsing as of now!


Known String 
Unknown (Maybe String)