From: Brian Candler <b.candler@...>
Date: 2009-07-22T19:29:14+09:00
Subject: Re: Default parameter values for methods in Ruby 1.9

I単aki Baz Castillo wrote:
> Hi, I expected that the following is valid in Ruby 1.9:
> 
>  def get_element(auid, document=nil, selector, check_etag=true)
>     [...]
>  end
> 
> However I get an error:
> 
>   syntax error, unexpected '=', expecting ')' (SyntaxError) ...,
>   element_selector, check_etag=true)
>                                ^
> 
> Thanks for any tip.

def get_element(auid, *rest)
  case rest.size
  ... etc
end

Are you saying that get_element(1,2) would use auid=1 and selector=2, 
but get_element(1,2,3) would use auid=1 and document=2 and selector=3? 
If so it might be slightly better documented as

def get_element(auid, document_or_selector, *rest)
  case rest.size
  when 0
    document = nil
    selector = document_or_selector
    check_etag = true
  when 1
    document = document_or_selector
    selector = rest[0]
    check_etag = true
  when 2
    document = document_or_selector
    selector = rest[0]
    check_etag = rest[1]
  else
    raise ArgumentError, "wrong number of arguments (#{rest.size}+2)"
  end
  ... etc
end

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