From: James Coglan <jcoglan@...>
Date: 2008-09-08T18:17:26+09:00
Subject: Re: Hash auto-true ({:a} == {:a => true})

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2008/9/8 Woody Peterson <woody.peterson@gmail.com>

> I have a unix-inspired desire to pass arguments to a method where some
> are toggle flags and some are values, aka "bash$ method --flag
> --config=/etc/method". I can think of a few ways to do it that are
> close, but if I had a hash that initiated value-less keys to true, I
> would have it.



If you make the restriction that flags always come first you could do
something like this:


def my_method(arg1, arg2, *args)
  options = (Hash === args.last) ? args.pop : {}
  puts args.inspect
  puts options.inspect
end

my_method('foo', 'bar', :flag, :value => 'something')
[:flag]
{:value=>"something"}

my_method('foo', 'bar', :flag)
[:flag]
{}

my_method('foo', 'bar', :value => 'something')
[]
{:value=>"something"}


Then you can check for flags using args.include?(:foo), or you could loop
over them and set them to true in the hash:

args.each { |key| options[key] = true }

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