From: Warren Young
Date: August 17 2008 12:22pm
Subject: Re: A way to copy mysqlpp::StoreQueryResult into a std::map?
List-Archive: http://lists.mysql.com/plusplus/7884
Message-Id: <2A8A08CA-8E44-496D-8C52-D966E2A0190C@etr-usa.com>
MIME-Version: 1.0 (Apple Message framework v928.1)
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
Content-Transfer-Encoding: 7bit

On Aug 17, 2008, at 4:09 AM, Alex wrote:

>> From looking at the example, it seems I have to use classes/structs  
>> to copy
> the data into a map. Is this correct? Or, can I just use a simple  
> function,
> or something?

The construct is called a functor:

	http://en.wikipedia.org/wiki/Function_object

Functors have several advantages over function pointers, which is why  
they're used throughout STL.  This feature of MySQL++ is modeled on  
STL algorithms like find_if().

It's true, they're rather heavy on the syntactic noise.  If C++  
supported anonymous (lambda) functions, we'd use them instead in  
places like this, but it doesn't, so we use functors.