From: Robert Feldt <feldt@...>
Date: 2001-03-05T17:05:30+09:00
Subject: [ruby-talk:11999] PLS-violation in proc as block method invocation!?

Hi,

I guess the following behavior is due to block/proc conversions
in method invocation but IMHO we should work to avoid it since
it violates PLS (Principle of Least Surprise) and have practical drawbacks
(I have a memoizer (caching results based on parameters) which should be
able to detect when called with the same block/proc):

$blocks = []
def m(&b)
  $blocks.push b
end
m {|i| i}
m {|i| i}
puts $blocks[0] == $blocks[1] # => false. Have to live with it, I guess...
p = proc{|i| i}
m(&p)
m(&p)
puts $blocks.inspect
puts $blocks[2] == $blocks[3] # => false. IMHO not "correct".

IMHO, the last statement should evaluate/print true and not false.
Or have I forgot some issue? Detailed explanations of
what's happening?

/Robert

Ps. 
$ ruby -v proc.rb
ruby 1.7.0 (2001-01-23) [i686-cygwin]
false
[#<Proc:0xa039ab0>, #<Proc:0xa039a80>, #<Proc:0xa039a20>,
#<Proc:0xa039a08>]
false