NAME

  pervasives.rb

SYNOPSIS

  access to pristine object state.  if you don't metaprogram you probably
  don't need it

INSTALL

  gem install pervasives

URIS

  http://rubyforge.org/projects/codeforpeople/
  http://codeforpeople.com/lib/ruby

SAMPLES

  <========< samples/a.rb >========>

  ~ > cat samples/a.rb

    #
    # Pervasives allows objects' method to be accessed in a pristine state, even
    # when some effort has been made to derride them
    #
      require 'pervasives'
    
      class OpenStruct 
        instance_methods.each{|m| undef_method m unless m[%r/__/]}
    
        def initialize
          @table = {}
        end
    
        def method_missing m, *a, &b
          case m.to_s
            when %r/[=]$/
              @table[m.to_s.delete('=')] = a.shift
            when %r/[?!]$/
              !!@table[m.to_s.delete('?!')]
            else
              @table[m.to_s]
          end
        end
    
        def inspect
          @table.inspect
        end
      end
    
      os = OpenStruct.new
    
      os.object_id = 42
      os.send = 42
      os.instance_eval = 42
    
      p os
    
      p os.object_id
      p Pervasives.object_id(os)
    
      p os.send
      p Pervasives.send(os, "key=", "value")
    
      p os.instance_eval
      p Pervasives.instance_eval(os){ @table }

  ~ > ruby samples/a.rb

    {"instance_eval"=>42, "send"=>42, "object_id"=>42}
    42
    -609487514
    42
    "value"
    42
    {"instance_eval"=>42, "send"=>42, "key"=>"value", "object_id"=>42}


  <========< samples/b.rb >========>

  ~ > cat samples/b.rb

    #
    # sometimes it may be more convenient to use a Pervasives::Proxy object
    # insteand of using Pervasives directly
    #
      require 'pervasives'
    
      class BlankSlate
        instance_methods.each { |m| undef_method m unless m =~ /^__/ }
    
        def object_id() 42 end
      end
    
      bs = BlankSlate.new
    
      proxy = Pervasives::Proxy.new bs
    
      p bs.object_id
      p proxy.object_id 

  ~ > ruby samples/b.rb

    42
    -609489100


  <========< samples/c.rb >========>

  ~ > cat samples/c.rb

    #
    # the special '__' method accesses an object's Pervasives::Proxy
    #
      require 'pervasives'
    
      class BlankSlate
        instance_methods.each { |m| undef_method m unless m =~ /^__/ }
        def object_id() 42 end
      end
    
      bs = BlankSlate.new
    
      p bs.object_id
      p __(bs){ object_id  }

  ~ > ruby samples/c.rb

    42
    -609486982


  <========< samples/d.rb >========>

  ~ > cat samples/d.rb

    #
    # it all works for classes too
    #
      require 'pervasives'
    
      class C
        def self.new() raise end
        def inspect() 42 end
      end
    
      p( Pervasives.new(C) )
      p( Pervasives::Proxy.new(C).new )
      p( __(C).new )

  ~ > ruby samples/d.rb

    42
    42
    42