From: Sean O'Dell <sean@...>
Date: 2003-11-20T06:35:41+09:00
Subject: Re: "stereotyping" (was: Re: Strong Typing (Re: Managing metadata about attribute types)

On Wednesday 19 November 2003 01:33 pm, Gavin Sinclair wrote:
> On Thursday, November 20, 2003, 6:37:50 AM, Sean wrote:
> > I'm only talking about checking that a certain interface is present. 
> > Just for the purpose of providing an informative error message when an
> > object which cannot fulfill the needs of a method is passed.  Right now,
> > it just explodes with an ugly message about something that happened deep
> > in the called method. Something more informative would go a LONG way.
>
> Nobody likes undescriptive error messages.  You're asking Ruby to do
> something about them, at a cost.  I prefer to believe that the cost
> should be on the library developer, who wishes to make life easier for
> his clients.
>
>   class LibraryClass
>     def library_method
>       # code ...
>     rescue SpecificError
>       # handle it
>     rescue => err
>       raise LibraryError, "library_method failed: #{err.message}"
>     end
>   end
>
> Granted, it doesn't often happen in real life, but it is better if the
> library author is putting some thought into the user experience,
> rather than feeling like he's jumping through hoops to keep an
> interface-checker happy.  A frustrated developer probably won't
> produce much code; in that case, at least we'd have less cryptic error
> messages, I suppose :)
>
> I'm not completely unsympathetic to what you're saying.  In fact, I'd
> like to read a detailed RCR.

Funny you should mention that.  =)

	Sean O'Dell