From: ebeard <ecbearden@...>
Date: 2006-10-06T03:45:11+09:00
Subject: Re: Better ruby way for caseing on class?

Hmmm.  This is the most interesting approach.

I was not aware of Kernel#lambda.

It's been creeping around like a wolfda in lambda's clothing. :)

ara.t.howard@noaa.gov wrote:
> On Thu, 5 Oct 2006, ebeard wrote:
>
> > I currently do this:
> >
> > [Kernel,String,Object].each do |klass|
> > case klass.to_s
> >  when 'Kernel' :
> >    puts 'I\'m doing stuff with object Kernel'
> >  when 'String' :
> >    puts 'I\'m doing stuff with object String'
> >  when 'Object' :
> >    puts 'I\'m doing stuff with object Object'
> >  end
> > end
> >
> >
> > Is there a better way?
>
> well, the code you have above is exactly equivalent to this
>
>    [Kernel, String, Object].each{|k| puts "I'm doing stuff with object #{ k }"}
>
> but i suppose your real code is quite different?  my point is just that
> looping over three things and selecting them each in turn is the same thing as
> pre-selecting the items to loop over.  another alternative is
>
>    actions = {
>      Kernel => lambda{ puts "I\'m doing stuff with object Kernel"},
>      String => lambda{ puts "I\'m doing stuff with object String"},
>      Object => lambda{ puts "I\'m doing stuff with object Object"},
>    }
>
>    [Kernel, String, Object].each{|k| actions[k].call}
>
> which works for some situations and can sometimes be even more general
>
>    actions = lambda{|k| lambda{ puts "I'm doing stuff with object #{ k }"} }
>
>    [Kernel, String, Object].each{|k| actions[k].call}
>
>
> which is suited to compact arg dependant actions but not long ones.
>
> regards.
>
> -a
> --
> in order to be effective truth must penetrate like an arrow - and that is
> likely to hurt. -- wei wu wei