From: "ara.t.howard" <ara.t.howard@...>
Date: 2008-06-19T14:14:09+09:00
Subject: Re: Rather validate values or use exceptions?


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