From: gabriele renzi <surrender_it@...1.vip.ukl.yahoo.com>
Date: 2003-12-15T19:01:57+09:00
Subject: Re: Arity?

il Mon, 15 Dec 2003 09:52:50 +0900, "Jon A. Lambert"
<jlsysinc@alltel.net> ha scritto::

>From the Programming Ruby - The Pragmatic Programmer's Guide:
>
>--class Proc ---
>arity  prc.arity -> anInteger
>
>Returns the number of arguments required by the block. If the block
>takes no arguments, returns -1. If it takes one argument, returns -2.
>Otherwise, returns a positive argument count unless the last argument
>is prefixed with *, in which case the argument count is negated. The
>number of required arguments is anInteger for positive values, and
>( anInteger +1).abs otherwise.
>
>Proc.new {||}.arity  � 0
>Proc.new {|a|}.arity  � -1
>Proc.new {|a,b|}.arity  � 2
>Proc.new {|a,b,c|}.arity  � 3
>Proc.new {|*a|}.arity  � -1
>Proc.new {|a,*b|}.arity  � -2

mh I het different results:

>> Proc.new do end.arity
=> -1 # no args
>> Proc.new do|| end.arity
=> 0 #0 args
>> Proc.new do|one| end.arity
=> 1 #one arg
>> Proc.new do|one,two| end.arity
=> 2 #two arg
>> Proc.new do|*maybenoargs| end.arity
=> -1 #no args (as minimum)


about the -2.. dunno :(