output_dir parameter for more decorators

[ghost]

The output_dir named parameter for @transform in combination with suffix(...) is a tremendously helpful simplification that allows for an explicit separation of directory structure(s) from file naming. Extending that to, e.g., subdivide might clarify the pipeline code for these cases.

[bunbun]

Thanks. This will be available in the next point release of ruffus 2.6.3 (?)

In the meantime, support is available in the git repository.

There is test code in test_suffix_output_dir.py.

Important:

For both
@tranform(suffix(...), output_dir = "something") and
@subdivide(suffix(...), output_dir = "something"),
the onus is on the Ruffus programmer not to do something senseless, like have a suffix() which includes a path / the parent directory:

    @transform(input = prev_task, filter = suffix("parent_dir/a.txt"), output = "parent_dir/b.txt", output_dir = "working_dir")
    def stupid_code(inputs, outputs):
        pass

There is no reasonable way of interpreting such code. Don't do it.