From: ara.t.howard@...
Date: 2005-11-29T03:20:09+09:00
Subject: Re: [BUG] string range membership

On Tue, 29 Nov 2005, Warren Brown wrote:

> Matz,
>
>>> What about Range#include??  Would it still be an
>>> alias for Range#member?, or would it retain the
>>> current interval check?
>>
>> No decided yet.  Feel free to say your opinion.
>
>    Well, I tend to agree with your previous decision on this.  Having
> Enumerable#include? be an alias for Enumerable#member? (or vice-versa),
> but having Range#include? behave differently from Range#member? would be
> confusing.  I think it would be better to leave these two methods as
> aliases and add a new method to Range for the interval check.  My
> leading candidate for this method is now David A. Black's suggestion of
> #encompass?.  This is a great name and I really like his idea of
> extending it to accept Ranges as parameters so that
> (1..10).encompass?(2..9) == true.  Other synonyms could also work:
> #enclose?, #surround?, and even #contain?.

reading this just gave me a new idea:  first of all, i think this method
should be a verb so that it implies a loop and test, rather than a simply
test.  this is important because the method is, potentally, extremely
expensive.  shortening you suggesting then, how about

   (0 ... 42).pass? 42  #=> false
   (0 .. 42).pass? 42  #=> false

for example:

   harp:~ > cat a.rb
   module Enumerable
     #
     # Enumerable#pass? member
     #   true if the each method will yield member
     #
       def pass? member
         each{|element| return(element ? element : true) if member === element}
         return nil
       end
   end

   p (0 ... 42).pass?(42)
   p (0 .. 42).pass?(42)
   p [0,1,2,nil].pass?(nil)

   open(".bashrc") do |f|
     if ((line = f.pass? %r/screen/))
       puts line
     end
   end


   harp:~ > ruby a.rb
   nil
   42
   true
   alias ss='screen -S '

thoughts?

-a
-- 
===============================================================================
| ara [dot] t [dot] howard [at] noaa [dot] gov
| all happiness comes from the desire for others to be happy.  all misery
| comes from the desire for oneself to be happy.
| -- bodhicaryavatara
===============================================================================