optional arguments with compact reporting in optparse

braver deliverable at gmail.com
Thu Nov 8 16:30:03 CET 2007

Posted to the Optik list, but it seems defunct.  Optik is now Python's

I wonder how do you implement optional arguments to Optik.  I.e., you
can have an option

-P [file]

-- the filename is optional, with a default "data,pikl".  It works as

-- if no -P is given, no pickle is written
-- if -P is given without the filename following, a pickle file is
written with the default name data.pikl
-- if -P filename is given, the pickle is written to filename

How do we do optional values in Optik, with nargs <= 1?

Another question I have it how can I output a docstring right from the
parser.add_option() block?  I prefer to define all option-related
things in the same block once.  I'd like to output the help value from
the block, or append it to a report.

Here's example from my Ruby wrapper for Ruby's optparse:

    name = :divisor
    help = "show divisor"
    short = "-m"
    opt.on(short, "--#{name} [STR]", help) do |val|
    	hash[:show_divisor] = true
    	hash[:divisor] = val if val
    report << [name,short,help]

-- notice that my report list is built with the exact values of all
options, regardless of whether they're encountered or not.  The I
simply walk through the report list to print a report for this run:

      report.each do |name,short,help|
        val = opts.name || "----"
        STDERR.printf "--%s (%s)\t\%s\t%s\n", o, short, val, help
      end if verbose

How can I group such reporting together with add_option in Optik?


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