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Subject: Re: [boost] Library for configuration file parsing
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2010-11-29 14:39:42

Denis Shevchenko wrote:
> On 29.11.2010 20:49, Hal Finkel wrote:
> > In my opinion, just provide a reload function.
> Already. There are two functions:
> - configurator::reparse()
> - configurator::reparse( const std::string& path_to_new_configuration_file )
> First variant for reparsing "old" configuration file, second - for
> reparsing new configuration file.

One cannot reparse what hasn't been parsed. I suggest "reparse" and "parse" or "reload" and "load" for those two functions. (The latter pair is slightly easier to say.)

Have you considered the ability to parse multiple files thereby augmenting the data with each new file's content rather than replacing what had been parsed already? In that case, the parse()/load() function would need to distinguish between replacing and augmenting the existing content or you'd need to distinguish the function names further:

   // reload contents from files used to generate current contents

   // replace current contents with that from a new file
   replace(std::string const &);

   // augment current contents with that from a new file
   append(std::string const &);

Do you support programmatic manipulations of the configuration values? That implies returning references to the configuration values or providing a pub/sub mechanism for learning of changes. That, in turn, means that reloading or replacing content must invalidate outstanding references/subscriptions (though subscriptions could survive if the value in question exists after the update and still refers to the same type, if there are types).

Do you support references among configuration values? Doing so permits some helpful use cases. (Just think about augmenting a shell's PATH versus replacing it outright.)

Rob Stewart robert.stewart_at_[hidden]
Software Engineer, Core Software using std::disclaimer;
Susquehanna International Group, LLP

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