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
enjoy and send in yer comments/patches!
-a
