From: Charles Comstock <cc1@...>
Date: 2004-02-21T08:09:52+09:00
Subject: Re: how to raise warning?

Andrew Johnson wrote:
> On Fri, 20 Feb 2004 17:25:17 +0900, Mark Hubbart <discord@mac.com> wrote:
> 
> 
>>I second that. Adding an optional boolean argument to the function to 
>>get different results doesn't quite seem rubyish to me.
> 
> 
> Well, it's certainly not unprecedented in Ruby:
> 
>   Range.new(start, end, exclusive=false)
>   load(filename, wrap=false)
>   obj.respond_to?(symbol, include_private=false)
>   obj.private_methods(all=true)
>   obj.protected_methods(all=true)
>   obj.public_methods(all=true)
> 
> 
> regards,
> andrew
> 

Right but not in things that print strings, the precedent there is not 
to use a boolean argument, since often you want to print multiple 
things.  I like the warn! idea though.  I would however say, that this 
is the classic use of a macro.  Most other uses of macro's we can 
replace with a call to eval.  But we lose the ability to do inplace code 
expansion which is so important for __LINE__ and things like that.  That 
and there is a way in C that you can get something to print out the name 
of the variable.  So you can have a macro that say:
v = 5

but your macro just says DEBUGV(v);

It seems like we might be able to do something like that with a symbol, 
but I haven't figured out how.

Charlie