From: Woody Peterson <woody.peterson@...>
Date: 2008-09-08T17:58:28+09:00
Subject: Hash auto-true ({:a} == {:a => true})

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.

Example:

method(:flag, :another, :config => "/etc/whatever")

For some of the functionality I colud use *args and check
args.include?(:foo), but then I couldn't pass in key-value pairs easily.

The closest way would be to use *args to pass in things of the form
method(:flag, [:config, "/etc/whatever"]), then use args.include?(:flag)
for flags and args.assoc(:config)[1] for value-based options.

Example:

method(:flag, [:config, "/etc/whatever"])

ex. code:

if args.include?(:flag) do; stuff; end
if args.assoc(:config) do; @config = args.assoc(:config)[1]; end

I'd have to make the args.assoc logic prettier with a helper method to
set up default values, but that's the basics of it. Much easier/prettier
if I could modify Hash to auto-assign empty keys to true. Note that
there's a way to set the default value for empty keys from nil to
another value (and even a proc), but this wouldn't be what I want. I
want empty keys to be nil, and specified lone keys set to true.

Thoughts? Anybody else think this would be really handy, or am I missing
something?
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