In message "[ruby-talk:01440] The return value of Method.arity"
    on 00/02/16, Dave Thomas <Dave / thomases.com> writes:

|I'm trying to come to grips with Method.arity. My understanding is
|that it returns the following
|
|  c language methods:  n mandatory arguments         +n
|
|                       n arguments including some    -n
|                       that are optional
|
|  attribute setters                                   1
|
|  Ruby methods         n arguments                    -n-1
|
|                       n arguments including an       -n
|                       array or block
|
|Is this correct?

Oops, it is a bug.  That should not be clear difference between C
methods and Ruby methods.  It should be

  methods: n mandatory arguments                +n
           n mandatory arguments + optional     -n-1

But C methods have no information about number of mandatory arguments,
so that arity for all C methods with any optinal arguments return -1.

							matz.