traverse_parent_directories: Perform an action repeatedly on parent directories until...
In robertzk/syberia: Syberia

Description Usage Arguments Value

Given a fn, we may wish to run it on a filepath, determine its success, and try again with the parent directory of filepath, until we obtain result that is not NULL. If this does not occur for any parent directory, we halt with the string error.

1	traverse_parent_directories(filepath, fn, error)

`filepath`	character. The filepath to traverse along. The `fn` function will be called with `filepath` and its parent directories until it returns a result other than `NULL`.
`fn`	function. A one-argument function called on `filepath` or its successive parent directories until a result other than `NULL` is returned, which will be the final return value.
`error`	character or function. A string to error if `fn` returns `NULL` on all parent directories, or a one-argument function to execute (the argument received will be the initial `filepath`)