From: James Edward Gray II <james@...>
Date: 2006-08-11T01:27:42+09:00
Subject: Re: good writing in Ruby...

On Aug 10, 2006, at 11:20 AM, Josselin wrote:

> Depending upon a variable 'user.role',
> I would like to  suppress all elements in the array , less or equal  
> to this variable
>
> ex :
> user.role = "a"    #=> roles = ["b", "c", "d", "e" ]    		"a" deleted
> user.role = "b"    #=> roles = ["c", "d", "e" ]   		"a", "b"  deleted
> user.role = "c"    #=> roles = [ "d", "e" ]   			"a", "b", "c" deleted
> user.role = "d"    #=> roles = [ "e" ]    				"a", "b", "c", "d"   
> deleted
> user.role = "e"    #  do nothing

See if this gives you some ideas:

 >> class User
 >>   def initialize
 >>     @roles = %w[a b c d e]
 >>     @role  = nil
 >>   end
 >>
?>   attr_accessor :role
 >>
?>   def roles
 >>     return @roles if @role.nil? or not (i = @roles.index(@role))
 >>
?>     @roles[0...i]
 >>   end
 >> end
=> nil
 >> user = User.new
=> #<User:0x322b00 @role=nil, @roles=["a", "b", "c", "d", "e"]>
 >> user.roles
=> ["a", "b", "c", "d", "e"]
 >> user.role = "c"
=> "c"
 >> user.roles
=> ["a", "b"]

James Edward Gray II