Re: [boost] Library for configuration file parsing

Subject: Re: [boost] Library for configuration file parsing
From: Sebastian Redl (sebastian.redl_at_[hidden])
Date: 2010-11-26 06:47:32

On 26.11.2010 12:11, Denis Shevchenko wrote:
> This is example of more complex configuration file:
> -------------------------------------------------------------------------------------- 
>
> /*
>  * more_complex.conf
>  */
>
> DbName       : my_database
> DbHost        : localhost
> DbPort         : 100
> DbUser         : some_user
> DbPassword  : some_password
>
> <Server>
>     Host           : 12.45.46.15               // IP semantic may be 
> check.
>     Port           :  1080                          // Value must be 
> unsigned integer number.
>     Admin/*this is comment with unnecessary info
>     asf*/istrator  : admin_at_[hidden]             // e-mail semantic 
> may be check.
>
>     StorePath     :  /some/path                            // path 
> semantic may be check.
>
> <Internal>
>         Logfile              : /some/path/to/logfile     // path 
> semantic may be check.
>         MaxLogFileSize  : 10 MB                           // size 
> semantic may be check, result in bytes.
> </Internal>
>
>     ReconnectPeriod : 10 m  // time-period semantic may be check, 
> result in seconds.
> </Server>
>
> <Plugins>
>     plugins  : a_plug   b_plug
>     plugins  : c_plug
>     plugins  : d_plug
>     plugins  : e_plug
> </Plugins>
> ---------------------------------------------------------------------------------------- 
>
PropertyTree could support such a format. However, it would not support 
schema support for configuration files, e.g. check semantics or 
automatically have default values available. It wouldn't be too hard to 
write a check for any given tree, though.

>
> I know boost::property_tree, this is very good library, but (imho) it 
> is designed specifically to advanced work with XML (though not only 
> with him).
No. The PTree XML parser is too basic to claim that it is for advanced 
work with XML. There is no support for advanced XML features at all.
> In other words, primaryarea of this library is notwork with 
> configuration files(imho).
IMO it is, and since I'm the maintainer, my opinion is not humble. :-)
> I could not find in the documentation (or in examples) of 
> boost::property_tree features such as option's default value or 
> necessary.
There is no schema definition or validation in PTree. However, there is 
the get_default function.
Schemas for PTree could be designed as a layer around PTree though.

Sebastian