lib.path.subpath.components: init

              ${subpathInvalidReason path}''

      ) 0 subpaths;

  /*

  Split [a subpath](#function-library-lib.path.subpath.isValid) into its path component strings.

  Throw an error if the subpath isn't valid.

  Note that the returned path components are also valid subpath strings, though they are intentionally not [normalised](#function-library-lib.path.subpath.normalise).

  Laws:

  - Splitting a subpath into components and [joining](#function-library-lib.path.subpath.join) the components gives the same subpath but [normalised](#function-library-lib.path.subpath.normalise):

        subpath.join (subpath.components s) == subpath.normalise s

  Type:

    subpath.components :: String -> [ String ]

  Example:

    subpath.components "."

    => [ ]

    subpath.components "./foo//bar/./baz/"

    => [ "foo" "bar" "baz" ]

    subpath.components "/foo"

    => <error>

  */

  subpath.components =

    subpath:

    assert assertMsg (isValid subpath) ''

      lib.path.subpath.components: Argument is not a valid subpath string:

          ${subpathInvalidReason subpath}'';

    splitRelPath subpath;

  /* Normalise a subpath. Throw an error if the subpath isn't valid, see

  `lib.path.subpath.isValid`

      expr = (builtins.tryEval (subpath.normalise "..")).success;

      expected = false;

    };

    testSubpathComponentsExample1 = {

      expr = subpath.components ".";

      expected = [ ];

    };

    testSubpathComponentsExample2 = {

      expr = subpath.components "./foo//bar/./baz/";

      expected = [ "foo" "bar" "baz" ];

    };

    testSubpathComponentsExample3 = {

      expr = (builtins.tryEval (subpath.components "/foo")).success;

      expected = false;

    };

  };

in

  if cases == [] then "Unit tests successful"