From: 7stud -- <bbxx789_05ss@...>
Date: 2008-02-20T15:44:31+09:00
Subject: Re: Need Help With OptionParser

Bryan Richardson wrote:
> Perfect!!! Thanks for the help.


I see several problems with that solution:

1) It uses an undocumented feature: the .options attribute of ARGV.

2) It uses the try/except mechanism which slows down your program when a 
exception actually occurs.

3) The fact that an option might not be a wrapper option is not an 
exceptional event--you regularly expect that to be the case.

4) It requires that you use a user defined array in place of ARGV.


Here's another solution:


require 'optparse'

p ARGV
puts

opts = OptionParser.new do |opts|

  #wrapper option where value is required:
  opts.on("-t=RANDOM_CHARS") do |val|
    puts "-t option entered with value=#{val}"

    opt_index = ARGV.index('-t')

    #delete option and its value:
    ARGV.delete_at(opt_index)  #rest of elements move one spot to the 
left
    ARGV.delete_at(opt_index)
  end

  #wrapper option where value is optional:
  opts.on("-y [=RANDOM_CHARS]") do |val|  #val==nil if no value for 
option
    puts "-y option entered with value=#{val}"

    opt_index = ARGV.index('-y')
    ARGV.delete_at(opt_index)

    if val
      ARGV.delete_at(opt_index)
    end

  end

  #non-wrapper option:
  opts.on("-a=RANDOM_CHARS") do |val|
    puts "-a option entered with value=#{val}"
  end

end


opts.parse(ARGV)
p ARGV


Problems with that solution:

I'm not thrilled with the code that deletes elements out of ARGV--that's 
inefficient because the rest of the elements have to be shuffled over 
one spot.  On the other hand, if I collect all the desired options into 
an array and then assign the array to ARGV, I get a warning:

warning: already initialized constant ARGV
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