From: Simon Strandgaard <neoneye@...>
Date: 2004-04-03T07:24:19+09:00
Subject: Re: Variable names

On Sat, 03 Apr 2004 02:20:24 +0900, David King Landrith wrote:
[snip] 
> Is there any way to access the name of a given variable instance from 
> within it?  In other words, for any object x, is there C function to 
> which I can pass self to determine that the program calls it 'x'?
> 
> Thanks,
> 

You want something like this ?

server> ruby a.rb
a.rb:4:in `should_be': expected String, but got Fixnum (TypeError)
        from a.rb:12:in `test'
        from a.rb:16
server> expand -t2 a.rb 
class Object
  def should_be(klass)
    unless self.kind_of?(klass)
      raise TypeError, <<-MSG.gsub(/^\s*/, '')
      expected #{klass}, but got #{self.class}
      MSG
    end
  end
end
def test(str)
  str.should_be(String)
end
test("hello")   
test(666)      # boom.. as we expect
server>

--
Simon Strandgaard