Re: [Boost-users] [date_time] is it possible to parse a string out from given patterns?

From: Yuval Ronen (ronen_yuval_at_[hidden])
Date: 2005-10-28 14:42:20

Jeff Garland wrote:
> On Wed, 26 Oct 2005 09:26:43 +0200, Roman Morokutti wrote
> 
>>Is it possible to parse a date out from a string
>>like this? The example below is from a java program.
>>
>>     private static final String PLANSTART_PATTERN = "dd.MM.yyyy HH:mm";
>>
> Yes, trivially.

IMHO, not trivial enough for such a trivial (and common) task.

> ptime
> parse_jdate1(const std::string& s)
> {
> 
>   ptime t;
>   try {
>     std::stringstream ss(s.c_str());
>     time_input_facet* timefacet = new time_input_facet("%d.%m.%Y %H:%M");
>     ss.imbue(std::locale(std::locale::classic(), timefacet));
>     ss.exceptions(std::ios_base::failbit); // turn on exceptions
>     ss >> t;
>   }  
>   catch(std::exception& e) {
>     std::cout << e.what() << std::endl;
>   }
>   return t;
> 
> }

I think the best way would be to support something like

ptime t;
my_istream >> time_format("%d.%m.%Y %H:%M") >> t;

time_format would be defined as something similar to

implemetation_defined time_format(const char *format, const std::locale 
&loc = std::locale::classic());

and using io manipulators it will do all the magic 
(facet/imbue/whatever) stuff automatically.

This will be much easier to use...

Just a thought,
Yuval