Re: [Boost-users] [xpression] fuzzy on smatch fields

From: Lynn Allan (l_d_allan_at_[hidden])
Date: 2006-04-11 23:59:25

Oops ... disregard .... redface .... Example 1 is related to "match" 
rather than "search" .... so I suppose prefix and suffix would not 
apply.

But, in example 2, seems like "year" should be repeat<1,4>, but:
year= repeat<1,2> works:

cregex date = (month= repeat<1,2>(_d)) // find the month ...
>> (delim= (set= '/','-')) // followed by a delimiter ...
>> (day= repeat<1,2>(_d)) >> delim // and a day followed by the same 
>> delimiter ...
>> (year= repeat<1,2>(_d >> _d)); // and the year.

actually, repeat<1,3> works for month, day, and year. Am I mixed up on 
what "repeat" means?

cregex date = (month= repeat<1,3>(_d)) // find the month ...
>> (delim= (set= '/','-')) // followed by a delimiter ...
>> (day= repeat<1,3>(_d)) >> delim // and a day followed by the same 
>> delimiter ...
>> (year= repeat<1,3>(_d >> _d)); // and the year.

Lynn Allan wrote:
> <alert comment="xpression newbie">
>
> Xpressive looks very promising to be able to do some things I'm 
> trying
> to implement. Thanks for providing and supporting it.
>
> I was trying to figure out the fields that make up xpression
> smatch'es, and expanded the Example-1 to be more verbose. Basically, 
> I
> tried to "unpack" as much info as I could find in the variable 
> "what"
> to clarify some fuzziness on my part. There were some questions:
>
> * The suffix and prefix info seemed blank. Are there accessors to 
> get
> more info to conform to my (possibly flawed) understanding of the
> docs?
>
> * The return from regex_id seemed to be an address (like 00323F58). 
> Is
> that intended? Is there some accessor to get something more
> meaningful? (but I'm not clear what would be meaningful). What is 
> the
> purpose of "regex_id" to the user of xpressive?
>
> * With vc7.1, there were warnings unless I cast the lengths and
> positions ... is this intended?
>
> void example1_verbose()
> {
> std::string hello( "hello world!" );
> sregex rex = sregex::compile( "(\\w+) (\\w+)!" );
> smatch what;
> if( regex_match( hello, what, rex ) )
> {
> std::cout << "Overall Size: " << static_cast<int>(what.size()) <<
> '\n';
> std::cout << "Regex Id: " << what.regex_id() << '\n';
> std::cout << "what[0]: " << what[0] << '\n';
> std::cout << "Length(0): " << static_cast<int>(what.length(0)) <<
> '\n';
> std::cout << "Position(0): " << static_cast<int>(what.position(0)) 
> <<
> '\n';
> std::cout << "Str(0): " << what.str(0) << '\n';
> std::cout << "what[1]: " << what[1] << '\n';
> std::cout << "Length(1): " << static_cast<int>(what.length(1)) <<
> '\n';
> std::cout << "Position(1): " << static_cast<int>(what.position(1)) 
> <<
> '\n';
> std::cout << "Str(1): " << what.str(1) << '\n';
> std::cout << "what[2]: " << what[2] << '\n';
> std::cout << "Length(2): " << static_cast<int>(what.length(2)) <<
> '\n';
> std::cout << "Position(2): " << static_cast<int>(what.position(2)) 
> <<
> '\n';
> std::cout << "Str(2): " << what.str(2) << '\n';
> std::cout << "Prefix(): " << what.prefix() << '\n';
> std::cout << "Prefix().matched: " << what.prefix().matched << '\n';
> std::cout << "Prefix().length(): " <<
> static_cast<int>(what.prefix().length()) << '\n';
> std::cout << "Prefix().str(): " << what.prefix().str() << '\n';
> std::cout << "Suffix(): " << what.suffix() << '\n';
> std::cout << "Suffix().matched: " << what.suffix().matched << '\n';
> std::cout << "Suffix().length(): " <<
> static_cast<int>(what.suffix().length()) << '\n';
> std::cout << "Suffix().str(): " << what.suffix().str() << '\n';
> }
> }
>
> Example 1: Verbose:
>
> Overall Size: 3
> Regex Id: 00323F58
> what[0]: hello world!
> Length(0): 12
> Position(0): 0
> Str(0): hello world!
> what[1]: hello
> Length(1): 5
> Position(1): 0
> Str(1): hello
> what[2]: world
> Length(2): 5
> Position(2): 6
> Str(2): world
> Prefix():
> Prefix().matched: 0
> Prefix().length(): 0
> Prefix().str():
> Suffix():
> Suffix().matched: 0
> Suffix().length(): 0
> Suffix().str():
>
> </alert>