From: Chris Carter <cdcarter@...>
Date: 2007-03-26T08:30:42+09:00
Subject: Re: Backus, Functional Programming, and Ruby

On 3/25/07, Jesse Merriman <jesse.d.merriman@gmail.com> wrote:
> On Sunday 25 March 2007 18:47, Devin Mullins wrote:
> > module Enumerable
> >    def inner_product
> >      transpose.map(&:*).inject(&:+)
> >    end
> > end
>
> That looks good, but is it right?
>
> irb(main):001:0> module Enumerable
> irb(main):002:1>   def inner_product
> irb(main):003:2>     transpose.map(&:*).inject(&:+)
> irb(main):004:2>   end
> irb(main):005:1> end
> => nil
> irb(main):006:0> [[0,1,2], [6,5,4]].inner_product
> TypeError: wrong argument type Symbol (expected Proc)
>         from (irb):3:in `inner_product'
>         from (irb):6
>
> $ ruby --version
> ruby 1.8.5 (2006-12-04 patchlevel 2) [i686-linux]
>
> --
> Jesse Merriman
> jessemerriman@warpmail.net
> http://www.jessemerriman.com/
>
>

He is assuming you have the famed "Symbol#to_proc" method, you can
find it with a quick google.

-- 
Chris Carter
concentrationstudios.com
brynmawrcs.com