From: Brian Candler <B.Candler@...>
Date: 2008-11-13T18:44:53+09:00
Subject: [ruby-core:19915] Re: Proposal: Method#get_args

On Thu, Nov 13, 2008 at 07:02:25AM +0900, Jim Weirich wrote:
> And while I strongly disagree with the design decisions on caller/ 
> backtrace (there is a lot of useful information in the strings that can 
> only be retrieved via brittle parsing), the args arrays proposed here 
> don't require parsing so are more in line with the other two  
> suggestions.

That does give me an idea. Since "?" is not legal in a variable name, then a
very simple option could be

   def foo(a, b, c=123, d=nil, *e, &blk)

     => ["a", "b", "?c", "?d", "*e", "&blk"]

   define_method(:bar) { |a,(b,c)|    }

     => ["a", ["b", "c"]]

The tuple alternative might be slightly easier to manipulate:

   [[:a,:req],[:b,:req],[:c,:opt],[:d,:opt],[:e,:rest],[:blk,:block]]

   [[:a,:req],[[[:b,:req],[:c,:req]],:group]]

but I don't think there's much in it.

(And I do realise that ?c has a different meaning in-line, but it's easier
to parse if the argument type discriminator is always the first character)