From: Matt Armstrong <matt@...>
Date: 2001-07-19T23:51:20+09:00
Subject: [ruby-talk:18123] Re: Exceptions

"Aleksei Guzev" <aleksei.guzev@bigfoot.com> writes:

> # 
> # No.  It requires deep core rewrite.  Not an easy task at all.
> # 
> # 							matz.
> 
> That is why I asked if anyone needs it. A friend asked me for such
> feature but I'm not sure if he really needs.

The argument I've heard against resumable exceptions is that they
require the exception handler know something about the internals of
the library in order to decide whether it is a good idea to resume or
not.  This turns exceptions into something more than a simple

    low -> high
    "Ooopse, hey higher level code, I'm giving up here!"

communication to

    low -> high
    "Hey higher level code, you didn't satisfy condition X!"

    high -> low
    "Whoopse, sorry, fixed, continue where you left off."

So a resumable exception is like an out of band message.  Obviously
useful for debugging, but I'm not sure Ruby needs it for anything else.