From: Yehuda Katz <wycats@...>
Date: 2008-11-16T08:17:38+09:00
Subject: [ruby-core:19957] Re: Proposal: Method#get_args

In our case, we're dealing with inbound web params, so the defaults  
are always strings.

Sent from my iPhone

On Nov 15, 2008, at 2:34 PM, "Roger Pack" <rogerpack2005@gmail.com>  
wrote:

>> We need the defaults to handle out-of-order defaults:
>> def action(bar=1, baz=2); end
>> Where we get {baz => 5} inbound.
>
> AFAIK this isn't possible in Ruby currently (though might work fine
> with "simple" values like you said).
>
> Some notes:
>
> Note that order matters:
> def action(bar=1, bar2 = bar1); end # valid but note that it needs
> bar1 to work, and needs it first
>
> def action(bar2 = bar1, bar1=0); end # invalid
>
> And then the "edge cases" where definitions include assignment are  
> hard:
>
> def action(bar=1, baz=(hidden_variable=2), foo=2*baz); end
>
> which, if you are given bar and foo, you can't recreate easily that
> hidden_variable == 2
>
> What you want might be something along the lines of
> object.__send_with_named_variables__ :action, :baz => 5
> though I'm not sure how it would work.
>
> With access to the AST you can write "wrappers" to methods [which
> still wouldn't help with the hidden_variable fella, except raising if
> you find it, but work besides that] [1].
>
> Was there a plan for named parameters in 2.0?  That might be the way  
> to go.
>
>
> -=R
>
> [1] http://code.google.com/p/ruby-roger-useful-functions/wiki/NamedParameters
>