version, component, summary changed; keywords, owner set

Tue, 09 Jan 2018 11:50:46 GMT

keywords predicate is_sorted algorithm less less_equal added
owner set to Marshall Clow
version Boost 1.63.0 → Boost Development Trunk
component None → algorithm
summary is_sorted() doc incorrectly says the predicate defaults to std::less_equal → Doc for is_sorted() incorrectly states the predicate defaults to std::less_equal

(Apologies for the description at the top being a mess. My original submission had external links in and I was forced to do a captcha. That failed over and over until I ended up trying to use browser "back" and "reload" to try to recover my original submission and eventually found I'd submitted an early draft.)

Second, terser version of lost text...

Doc for is_sorted() says:

If no comparison predicate is specified, then std::less_equal is used (i.e, the test is to see if the sequence is non-decreasing)

That's not true, it's std::less - see line 60 of boost/algorithm/cxx11/is_sorted.hpp.

This code confirms the default behaviour matches std::less not std::less_equal.

#cpp
int main () {
  std::vector<int> a        = { 1, 2, 2, 3 };
  std::cerr << "default   : " << std::boolalpha << boost::algorithm::is_sorted( a                      ) << "\n";
  std::cerr << "less      : " << std::boolalpha << boost::algorithm::is_sorted( a, std::less      <>{} ) << "\n";
  std::cerr << "less_equal: " << std::boolalpha << boost::algorithm::is_sorted( a, std::less_equal<>{} ) << "\n";
}

I vote: change docs, not code. Because: that matches std::.

Boost C++ Libraries: Ticket #13383: Doc for is_sorted() incorrectly states the predicate defaults to std::less_equal

version, component, summary changed; keywords, owner set