From: Sam Smoot <ssmoot@...>
Date: 2008-06-20T01:13:41+09:00
Subject: Re: Rather validate values or use exceptions?

On Jun 19, 12:14 am, "ara.t.howard" <ara.t.how...@gmail.com> wrote:
> On Jun 18, 2008, at 7:23 PM, Sam Smoot wrote:
>
> > Exceptions are _orders of magnitude slower_ than normal flow-control
> > structures.
>
> only when they occur - having a rescue block defined cost next to  
> nothing on most cases.  the best approach is often to *try* to use  
> conditional structures but to still use the rescue block - but that  
> ends up being very verbose and i'm personally no fan of the common  
> rails pattern of using AR in such a fashion that the 'db ought to  
> maintain integrity'.
>
> so while i totally agree with you i also see *way* too much ruby code  
> written as
>
> unless File.exists?( pidfile )
>    # race condition
>    create_pidfile pidfile
>
> which races on a normal fs and races *badly* on standard production  
> shared filesystems like NFS.  so, although exceptions might be slow,  
> i'll take them over code that works 'most of the time' any day -  
> although, if code is going to blow up i do like it to do so order of  
> magnitude more quickly ;-)
>
> just my two cents on the issue - not responding to your post  
> directly.  i guess i would summarize by saying that i totally agree,  
> but that there are *far* more exceptional behaviours in the real world  
> that much code seems to be acknowledge.
>
> cheers.
>
> a @http://codeforpeople.com/
> --
> we can deny everything, except that we have the possibility of being  
> better. simply reflect on that.
> h.h. the 14th dalai lama

No, you're right, agree 100%.

I'm more thinking of seeing people raise/catch exceptions for
validation. Or a locked record in the database. Basically using them
like a GOTO. And they're really functionally identical to throw/catch
in those situations, because you don't _really_ care about the stack-
trace that produced a validation error. It's a case you can handle.

On the other hand, ArgumentError is my favorite thing since sliced
bread. ;-) No, I can't pass a Symbol, String, Integer, Array or Hash.
Pick one. Even if I have to type a couple more characters. At least I
won't forget the method signature. :-)

/off topic