From: grady@... (Steven Grady)
Date: 2000-12-01T03:40:03+09:00
Subject: [ruby-talk:6682] behavior of Proc#arity?

I was looking at the library reference, and I have to say I'm confused
about the behavior of Proc#arity.  First, note that the reference
is now wrong.  It says that Proc.new {|a|}.arity returns -2, when it
has been fixed (?) to return -1.  So given that, why do all the following
argument specifiers:
    ||
    |a|
    |*a|
return -1, while there is nothing that returns 0 or 1?  Following
the POLS, I would have expected:
    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
    Proc.new {|a, b, *c|}.arity -> -3
Doesn't this make more sense?

BTW, as far as I can tell, nothing currently uses "arity", so if this
were a reasonable change, there shouldn't be any real problems with
backwards-compatibility..
--
	Steven
"Mind your manners, son!  I've got a tall pointy hat!"