From: Joel VanderWerf <vjoel@...>
Date: 2008-08-09T04:30:06+09:00
Subject: Re: ruby wish-list

Mikael H�ilund wrote:
> Perhaps a bit controversial, but I'd like to see a keyword for the 
> �current block� as a way to refer to the Proc instance created inside 
> that block. That would allow for recursive anonymous blocks like:
> 
> [[1,2,[3]],[[[5],6],7],8].map { |e|
>   Array === e ? e.map(&current_block) : e.to_s
> }
> 
> without resorting to ugly syntax like
> 
> [[1,2,[3]],[[[5],6],7],8].map &(deep_to_s = proc { |e|
>   Array === e ? e.map(&deep_to_s) : e.to_s
> })
> 

IIUC, this would also let us take this idiom:

pr = proc {|h,k| h[k] = Hash.new(&pr)}
h = Hash.new(&pr)
h[1][2][3] = 6
p h   # ==> {1=>{2=>{3=>6}}}

and simplify to:

h = Hash.new {|h,k| h[k] = Hash.new(&current_block)}

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407