From: Alan Chen <alan@...>
Date: 2002-07-19T09:31:02+09:00
Subject: Re: Can you only catch errors one level deep?

On Fri, Jul 19, 2002 at 09:04:02AM +0900, Philip Mak wrote:
[previous writing dropped]

> The problem with "rescue LoadError" is that it will also catch errors
> it wasn't meant to! In my case, the file it loaded existed, but
> requiring that file threw a LoadError because there was some other
> problem with it. So the "rescue" caught an error it wasn't meant to
> catch, and just made debugging harder.

What errors did rescue LoadError catch? Where they derived from LoadError?

> This seems to be an inflexibility with the begin/rescue/end construct.
> If 'require' was a function that returned a false value upon failing
> to load its argument, then the code could have done this:
>
> Any thoughts about this inflexibility of the begin/rescue/end system?

I'm not sure it's really an inflexibility of the rescue system. I
think you're just trying to assign more subtle semantics to the
LoadError exception.  I take LoadError to mean that there is an error
preventing the the required code to operate correctly. Maybe
the file doesn't exist, or there's a syntax error in the required 
code, or you need to load a dependency of the required file first.

If you want better debugging, you could log the details of the
LoadError, even if you have a specific action to recover.

- alan

-- 
Alan Chen
Digikata LLC
http://digikata.com