From: dblack@...
Date: 2003-08-20T00:43:05+09:00
Subject: Re: $VERBOSE=true returns warnings from standard library

Hi --

On Tue, 19 Aug 2003, Gavin Sinclair wrote:

> On Wednesday, August 20, 2003, 12:02:24 AM, Dave wrote:
>>
> > Could we not make it a rule that stuff in the standard library has to
> > meet a basic standard? Rather than disable warning in the library code,
> > could we instead fix the warnings?

I third this (see Hugh's second :-)

> That's a good idea, but in the specific case of "redefine ...", I
> think a different approach may be needed.
>
> Ruby allows you to redefine methods, and the Ruby community encourages
> people to take advantage of that.  Yes the Ruby interpreter issues a
> non-negotiable warning when you do so.  Perhaps a warning should *not*
> be given (by default) in this case.  It could be given when the user
> asks for maximum warnings.

The original post was about "redefine instance" in singleton.rb, not
the classic "method redefined, discarding old xxx" warning.  But
on the latter subject:

> For instance, I consider this good style:
>
>   class Example
>     attr_accessor :attribute
>
>     # ...
>
>     def attribute=(x)
>       # something special
>     end
>   end
>
> It lets the reader know up front that they can use #attribute and
> #attribute=, and then it changes the implementation, which the casual
> reader doesn't need to know - do they?

I don't know, but I think the casual reader -- at least, *that* casual
-- isn't all that major a player in the game, at least not to the
point where attr_accessor's documentation role outweighs its
method-defining role, which I think is happening here.  It seems that
you're defining a method you don't need, solely for the purpose of
documenting it, which seems a bit loose.

I think the discarding method warning is potentially useful for a
case like:

  class C
    def x; end
    def xx; end
    def xx; end  # whoops, meant to type xxx
  end

where you accidentally trample a method.  It's a fairly marginal
scenario, but it's probably best to have it issue a warning just in
case.


David

-- 
David Alan Black
home: dblack@superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav