Steve, I have another question about this. In boost document about Posix basic regular expression syntax, a section beginning \( and ending \) is defined as a marked sub-expression. In Posix Extended Regular Expression Syntax, A section beginning ( and ending ) is defined as a marked sub-expression. May I say regex class or regex_match support ERE instead of BRE by default? Thanks, Qihong On Tue, Mar 17, 2009 at 10:43 PM, Steven Watanabe <watanabesj@gmail.com>wrote:
AMDG
Qihong Wang wrote:
I'm a new boost and regex user. I tried a c++ regex sample as follows
regex pattern("banan\\(an\\)*a"); string str = "bananana";
if(regex_match(str, pattern)) cout<<"---- pattern matched ----"<<endl; else cout<<"---- pattern unmatched ----"<<endl;
To my surprise, the it printed out pattern unmatched. If I change str to "banan(an)a", the result is pattern matched. Feels like boost.Regex doesn't treat ( ) as subexpression. Any idea?
You're escaping the parentheses, so Boost.Regex, treats them as literal "(" and ")" instead of special characters. The regex will match strings like "banan(an)))))a"
In Christ, Steven Watanabe
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