Quuxplusone added inline comments.
================ Comment at: libcxx/test/std/re/re.traits/lookup_classname_user_defined.pass.cpp:46 + // matches all characters (they are classified as alnum) + std::wstring re1 = L"([[:alnum:]]+)"; + std::regex_search(in, m, std::wregex(re1)); ---------------- timshen wrote: > Quuxplusone wrote: > > Could you add a test here for > > > > std::wstring re3 = L"([[:ALNUM:]]+)"; > > std::regex_search(in, m, std::wregex(re3, std::regex_constants::icase)); > > > > std::wstring re4 = L"(\\W+)"; > > std::regex_search(in, m, std::wregex(re4, std::regex_constants::icase)); > > > > documenting the expected outputs? It's unclear to me from cppreference > > http://en.cppreference.com/w/cpp/regex/regex_traits/lookup_classname > > whether lookup_classname("W") is supposed to produce a result or not (but > > you seem to assume it does). > > > > My understanding is that the "icase" parameter to lookup_classname is > > talking about the icaseness of the regex matcher; classnames should always > > be matched with exact case, i.e. `[[:alnum:]]` is always a valid classname > > and `[[:ALNUM:]]` is always invalid, regardless of regex_constants::icase. > > But I'm not sure. > [re.req] says that, for lookup_classname(), "The value returned shall be > independent of the case of the characters in the sequence." > > I take it as regardless of lookup_classname()'s icase argument, [[:ALNUM:]] > is always valid. > > There are existing tests that confirms it in > std/re/re.traits/lookup_classname.pass.cpp. Search for "AlNum". > > I fixed my patch, since I was misunderstanding it as well (I thought icase is > for the input char sequence). Now they are just forwarded into > lookup_classname(). > [re.req] says that, for lookup_classname(), "The value returned shall be > independent of the case of the characters in the sequence." Huh. That seems like a defect in the Standard, since although lookup_classname() is parameterized on a locale, there is no standard way to get case-insensitive string comparison out of an arbitrary locale AFAIK. However, that's a problem for the implementer of lookup_classname(), not for you. Forwarding straight to lookup_classname() and letting it deal with questions of "case" sounds like the right approach to me. If you *wanted* to go down this rabbit hole, a good test case would be `"[[:DIGIT:]]"` in Turkish locale (where lowercasing `"[[:DIGIT:]]"` produces `"[[:dıgıt:]]"` not `"[[:digit:]]"`). (Note— The only place I find "case-insensitive" in N4659 is in the informative note on `time_get::get`: "It is unspecified by what means the function performs case-insensitive comparison or whether multi-character sequences are considered while doing so." —end note) https://reviews.llvm.org/D37958 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
