Re: philosophical question

On 13 August 2004, Eric O. Angell said:
> What is the intended purpose of option groups?

David Goodger could give the canonical answer, since he wrote that
feature (for Docutils).  But as I understand it, option groups are
purely for documentation purposes -- grouping related options together,
indented under a common heading, makes long help output easier to read.
If you have Docutils installed, run (eg.) "rest2html --help" to see an
example.

That is, all of the OptionGroups in one OptionParser are for a single
script.  They're *not* intended for your use, ie. a script with
sub-commands.


> I'm writing a script that has
> several different possible actions, each of which are affected by a mostly
> disjoint set of options.  It seemed to make sense to me to separate the
> options for each action by putting them in different option groups so that the
> help message prints in a reasonable manner, which works almost beautifully.

The standard answer to this is to use a separate OptionParser for each
subcommand.  Generating help output that looks "just right" is an
exercise left for the reader.  (Although this question comes up often
enought that I suppose Optik should grow some support for sub-commands.
Or at least the docs should cover it.  Hmmm.)

> You're probably going to tell me that my script is behaving too much like tar
> in requiring a command as an argument, huh?

My problem with tar is that the commands are single letters and they're
not really distinguishable from options.  The right model (IMHO) is cvs:

  cvs ci
  cvs log
  cvs status

which astute readers will have noted provides the model for the
distutils:

  python setup.py build
  python setup.py install
  python setup.py sdist

I think that's a perfectly reasonable way to organize a program with
several very different modes of operation.  Optik doesn't prevent you
from doing this, but it doesn't provide any explicit support for it
either (yet).

        Greg
-- 
Greg Ward <[email protected]>                         http://www.gerg.ca/
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