From: Hal Fulton <hal9000@...>
Date: 2006-02-15T14:50:03+09:00
Subject: Re: Rescuing blocks?

Dave Cantrell wrote:
> Eric Hodel wrote:
> 
>>
>> You're going to get a performance hit setting up an exception trap 
>> this way.
> 
> Time for some down-South edumucation. What kind of performance hit are 
> we talking about here? And why the hit at all?
> 
> (I seem to recall reading somewhere once upon a time about memory stack 
> stuff, but I'm not an old-school C-programmer so I never had to deal 
> with it --- unfortunately for me...)

Well, my knowledge is limited. Someone else can answer better.

But look at it from a common-sense standpoint. Exceptions aren't
magic. Everything Ruby does can be done in assembly language, it's
just more verbose.

I would think that exceptions, at the lowest level, work something
like:

    if something_happened_here
       goto the_place_where_exceptions_are_caught

So at the very least, catching exceptions means that you're doing
some sort of comparison or conditional branch. And this is code
that doesn't have to be run/generated *unless* you are catching
exceptions.

Just my naive take.


Hal