Hi,

In message "[ruby-talk:28422] why is Proc's arity function so weird?"
    on 01/12/14, Paul Brannan <paul / atdesk.com> writes:

|Why does arity return -1 when there is 1 argument?  The problem with
|this is the following:

If you want to specify ONE argument you have to specify

  Proc.new{|a,|}

not

  Proc.new{|a|}

I agree this may against PoLS, but life is not that simple.
This is the biggest shortage of Ruby.  I will try to fix it in the
future.

							matz.