append

lib.path.append

Docs pulled from | This Revision | 10 minutes ago

Append a subpath string to a path.

Like path + ("/" + string) but safer, because it errors instead of returning potentially surprising results. More specifically, it checks that the first argument is a path value type, and that the second argument is a valid subpath string.

Laws:

Not influenced by subpath normalisation:

append p s == append p (subpath.normalise s)

Inputs

path: The absolute path to append to
subpath: The subpath string to append

Type

append :: Path -> String -> Path

Examples

`append` usage example

append /foo "bar/baz"
=> /foo/bar/baz

# subpaths don't need to be normalised
append /foo "./bar//baz/./"
=> /foo/bar/baz

# can append to root directory
append /. "foo/bar"
=> /foo/bar

# first argument needs to be a path value type
append "/foo" "bar"
=> <error>

# second argument needs to be a valid subpath string
append /foo /bar
=> <error>
append /foo ""
=> <error>
append /foo "/bar"
=> <error>
append /foo "../bar"
=> <error>

Noogle detected

Implementation

The following is the current implementation of this function.

append =
    # The absolute path to append to
    path:
    # The subpath string to append
    subpath:
    assert assertMsg (isPath path)
      ''lib.path.append: The first argument is of type ${builtins.typeOf path}, but a path was expected'';
    assert assertMsg (isValid subpath) ''
      lib.path.append: Second argument is not a valid subpath string:
          ${subpathInvalidReason subpath}'';
    path + ("/" + subpath);