Re: Practicalities of Ada for app development

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Thu, 14 Jun 2012 10:39:49 +0200, Yannick Duchêne (Hibou57) wrote:

> Le Thu, 14 Jun 2012 09:58:10 +0200, Dmitry A. Kazakov  
> <mailbox@dmitry-kazakov.de> a écrit:
> 
>> On Wed, 13 Jun 2012 20:21:26 -0700 (PDT), quiet_lad wrote:
>>
>>> On Jun 13, 6:09 am, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
>>> wrote:
>>>> On Wed, 13 Jun 2012 03:35:05 -0700 (PDT), quiet_lad wrote:
>>>>> What does one do then with say 1000 websites on 1 web appserver? If
>>>>> not use patterns?
>>>>
>>>> Especially in such cases. Pattern matching (even RE) is a very  
>>>> expensive
>>>> thing, eats lot of resources.
>>
>>> so what does one do? how do you match say name based virtual hosts on
>>> aws?
>>
>> What is the problem? I cannot decipher "match say name based virtual  
>> hosts
>> on aws."
>>
> 
> Web addresses have a domain name and a TLD, like in adalog.fr. The server  
> is reached via DNS request returning the IP addresse for the domain. Web  
> addresses may also have subdomains. An example could be archive.adaic.com.  
> “archive”, is a subdomain of adaic.com. To reach the subdomain, you have  
> to contact the server at the IP address associated to the domain  
> adaic.com. That means archive.adaic.com has the same IP address as  
> adaic.com. The same goes for any other subdomain like news.mysite.net,  
> forum.mysite.net, wiki.mysite.net and so on, all reached via mysite.net's  
> IP.

I still see no problem stated. Maybe maps or suffix tree (I am guessing).
Certainly not patterns.

The rule of thumb for patterns: they are used exclusively as the user
input, when he is asked to specify some set of string.

Patterns should never be used internally, because there always exist a
better method of handling a set of strings, since almost always the set of
strings from the problem domain is different from the formal language of
the patterns. Either it is stronger and patterns simply do not work, or it
weaker and thus patterns become too inefficient compared to specific
methods. 

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de