From: Brett Williams <brett_williams@...>
Date: 2004-08-24T05:25:47+09:00
Subject: optparse [feature request: subcommand support]

After 2 1/2 years, it looks as if I'll finally get off of my old CVS
snapshot of ruby 1.7.2 (phew!). As a result, I can now look at using a
lot of the huge new standard library.

optparse is one I'm particularly interested in. Earlier this year I saw
it, and since I couldn't use it, I copied some of its features as it
seems to be much better than getoptlong. I'm missing some of them which
I want, however (type coercion and keyword completion principally). I'd
like to convert my stuff over to the OptionParser when 1.8.1 gets rolled 
out.

I do have one feature that optparse appears to lack, and I'm just
wondering if there is any interest in it (here's the feature request).

The feature is the ability to do what I call CVS-style subcommands, i.e.:

vor-lord:scaf_flow/scaf_flow> cvs help
Unknown command: `help'

CVS commands are:
add      Add a new file/directory to the repository
admin    Administration front end for rcs
annotate Show last revision where each line was modified
checkout Checkout sources for editing
commit   Check files into the repository
....

I then want to be able to have options that are local to a subcommand,
as well as global options, i.e.:

Usage: cvs [cvs-options] command [command-options-and-arguments]


The implementation of this should be quite trivial. (In my own
implementation I just have a hash of objects, one of which is a default
object, which is operated on when no name is given. That said, I don't
know much about the structure of OptionParser and it may not
lend itself to an easy modification such as this).

For example, one could do something like:

opts.on('-r', '--recursive', 'operate recursively') do
   ...
end
opts.on_cmd('admin', '-r', '--remove', 'removes something') do |arg|
   ...
end

As such things can even be reused (as in the above example, -r can be
global or local, or both):

foo -r admin -r '*Helper*'

There would need to be a little bit of smarts in the usage string 
generator, but by and large it doesn't seem to be too difficult.

Does this sound reasonable? Is there anyone else who'd like this kind of
thing? Or am I on my own?

Thanks for reading this far.  I didn't find anything related to this in 
a search of the archives (hopefully I didn't miss anything).