Import groups
=============

See also use_lines.txt

As a less verbose alternative to per-file imports, there could be some kind
of "import groups" feature.

In the per-module imports.txt file (or whatever filename will be used):

    # Common imports (always imported)
    std String
    std List

    group Backend
        binary BinBuffer
    end

    group Parser
        mini_ll MLLParser
    end

And in .slul files:

    use group Backend

Alternative solutions
---------------------

* Have per-directory imports.txt/dependencies.index files
  (require it to be present in all modules?)

* Have sub-modules, and no per-file imports at all.