From: Philip Mak <pmak@...>
Date: 2002-10-17T15:51:03+09:00
Subject: Re: How to tell if a method accepts this many arguments?

On Wed, Oct 16, 2002 at 09:27:09PM -0400, Philip Mak wrote:
> there is a Method#arity method, but if the method takes a variable
> number of arguments, Method#arity only tells me the minimum number
> of arguments, not the maximum number.

Thinking more about this, wouldn't it make more sense for Method#arity
to return a Range? e.g.:

def x(a, b)          # arity is 2..2
def x(a, b, c = nil) # arity is 2..3
def x(a, b, *arr)    # arity is 2..Infinity (yes, Ruby supports
                     # infinite ranges)

Then I could use the Range#=== operator to determine whether that's
too many arguments. e.g.:

    if the_method.arity === args.length
        the_method.call *args
    else
        puts "Invalid number of arguments to command."
    end