From: "Peña, Botp" <botp@...>
Date: 2007-09-11T19:01:36+09:00
Subject: Re: Bug in lambda?

From: Robert Klemme [mailto:shortcutter@googlemail.com] 
# Actually the original issue was different IIRC, because the block was 
# defined in a scope which had the block parameter as a local variable 
# which is not the case in your example.

nonetheless, it is still dangerous on procs/lambda
these block arg var creeping scope just adds to the confusion and danger

simple example (got this fr avi's post),

botp@pc4all:~$ irb
irb(main):001:0>
irb(main):002:0* x="this is a test"
=> "this is a test"
irb(main):003:0> fac = lambda{|x| if x == 0 then 1 else fac.call(x - 1) * x end}
=> #<Proc:0xb7dcda90@(irb):3>
irb(main):004:0> puts fac.call(3)
0
=> nil
irb(main):005:0> quit
botp@pc4all:~$ irb
irb(main):001:0> fac = lambda{|x| if x == 0 then 1 else fac.call(x - 1) * x end}
=> #<Proc:0xb7d6542c@(irb):1>
irb(main):002:0> puts fac.call(3)
6
=> nil

kind regards -botp