From: "Perl J." <perljunkie@...>
Date: 2011-09-26T08:08:21+09:00
Subject: Re: Looking for better/familiar approach to command line opts

Wow, time being what it is, I just need to post to a forum sooner. :-)
It never fails that when I post to a forum asking for help, immediately
thereafter I figure it out.

It turns out that the original code I posted in Ruby... WORKED.  Exactly
as I wanted it to.  I was just making a stupid, dumb rookie mistake.
This is exactly what I want.  Now there might be a better way to do it,
but this produces the results I want:

require "optparse"

class Options
   attr_reader :args, :cmdline, :options_list
   def initialize( options )
      @cmdline = ARGV.join( ' ' )
      @options_list = options.values.join
      params = ARGV.getopts( @options_list )
      options.each do |key,value|
         value.sub!( /:/, '' )
         self.class.send( :define_method, key ) { params[value] }
      end
      @args = Array.new( ARGV )
   end
end

options = Options.new({
   :source_path => 's:',
   :dest_path   => 'd:',
   :verbose     => 'v',
})

puts "Source path.......: #{options.source_path}"
puts "Destination path..: #{options.dest_path}"
puts "Verbose is........: #{options.verbose ? 'ON' : 'OFF'}"
puts "Command line was..: #{options.cmdline}"
puts "Arguments.........: #{options.args.join( ' ' )}"
puts "getopts() list....: #{options.options_list}"

Returns:

pj@matrix-dhcp-191:~/Work/Clients/Nunya/Business> ./bkupct.rb -s dude -d
yo purge them all split
Source path.......: dude
Destination path..: yo
Verbose is........: OFF
Command line was..: -s dude -d yo purge them all split
Arguments.........: purge them all split
getopts list......: s:d:v

The rookie mistake is that there was a mismatch between the values in
the options I passed into the class to initialize() and the value I am
using to index the elements of the returned params hash in initialize().
The params hash is indexed using just the letters, whereas options still
has the colons which getopts needs.  The closure I was expecting to
create with the params hash was working, it was just indexing wrongly.
So a simple sub! took care of this and now it works EXACTLY as I would
like.

Now, if someone can explain to me WHY I had to call the define_method()
method using send() instead of calling it outright, I'd really like to
know  why that is.  Why can't I do this?:

class Options
   attr_reader :args, :cmdline, :options_list
   def initialize( options )
      @cmdline = ARGV.join( ' ' )
      @options_list = options.values.join
      params = ARGV.getopts( @options_list )
      options.each do |key,value|
         value.sub!( /:/, '' )
         ## Why can't I just do this?!
         self.define_method( key ) { params[value] }
      end
      @args = Array.new( ARGV )
   end
end

Thanks all!
-pj

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