From: "Wolfgang Nádasi-Donner" <ed.odanow@...>
Date: 2007-10-02T18:48:25+09:00
Subject: binding_of_caller

Moin, moin!

I didn't find a topic which tells me, if a method "binding_of_caller" is
planned for Ruby's future. There was a method available via a library,
but it doesn't work anymore, because it was based on a bug (a nice bug,
indeed).

I would like to have a method like this, because it avoids unnecessary
parameters under some circumstances.

The actual example was a the answer to a variable reference, which was
needed by some member of the german Ruby forum.

>>>>> Code >>>>>
module Kernel
  def ref(v, bnd)
    v = v.to_s
    eval('lambda{|*p|p.length==0 ? ' + v + ' : ' + v + '=p[0]}', bnd)
  end
end

class Proc
  def -@
    self[]
  end
  def <<(v)
    self[v]
  end
end

a = 42
b = 84

x = ref :a, binding # unfortunately necessary
y = ref :b, binding # unfortunately necessary

puts a        # => 42
puts -x       # => 42
puts b        # => 84
puts -y       # => 84

puts x << 55  # => 55
puts a        # => 55
puts -x       # => 55

z = ref :y, binding # unfortunately necessary

puts b        # => 84
puts --z      # => 84

puts -z << 75 # => 75
puts -y       # => 75
puts --z      # => 75
puts b        # => 75
>>>>> EoC >>>>>

Wolfgang Nádasi-Donner
-- 
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