Error when compiling and using extract function

[jokteur]

Hello,

I discovered this library because I need fuzzy search in my program. I have the case that I am comparing one string against a multiple string, so I am using the extract function as shown in the readme:

template <typename Sentence1,
          typename Iterable, typename Sentence2 = typename Iterable::value_type>
std::vector<std::pair<Sentence2, double>>
extract(const Sentence1& query, const Iterable& choices, const double score_cutoff = 0.0)
{
  std::vector<std::pair<Sentence2, double>> results;

  rapidfuzz::fuzz::CachedRatio<typename Sentence1::value_type> scorer(query);

  for (const auto& choice : choices) {
    double score = scorer.similarity(choice, score_cutoff);

    if (score >= score_cutoff) {
      results.emplace_back(choice, score);
    }
  }

  return results;
}

I am using it like this:

auto search_results = extract<std::string, std::vector<std::string>>(query, terms);

However, I encouter this compilation error:

C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\include\xstring(2397,61): error C2338: The character type of basic_string must be a non-array trivial standard-layout type. See N4861 [strings.general]/1. [C:\[...].vcxproj]
[build] C:\[...]\external\rapidfuzz-cpp\rapidfuzz/fuzz.hpp(68): message : see reference to class template instantiation 'std::basic_string<CharT1,std::char_traits<CharT1>,std::allocator<std::string>>' being compiled [C:\[...].vcxproj]
[build]           with
[build]           [
[build]               CharT1=std::string
[build]           ]
[build] C:\[...]\src\ui\search\search.cpp(17): message : see reference to class template instantiation 'rapidfuzz::fuzz::CachedRatio<Sentence1>' being compiled [C:\[...].vcxproj]
[build]           with
[build]           [
[build]               Sentence1=std::string
[build]           ]
[build] C:\[...]\src\ui\search\search.cpp(113): message : see reference to function template instantiation 'std::vector<std::pair<std::basic_string<char,std::char_traits<char>,std::allocator<char>>,double>,std::allocator<std::pair<std::basic_string<char,std::char_traits<char>,std::allocator<char>>,double>>> Search::extract<std::string,std::vector<std::string,std::allocator<std::string>>,std::basic_string<char,std::char_traits<char>,std::allocator<char>>>(const Sentence1 &,const Iterable &,const double)' being compiled [C:\[...].vcxproj]
[build]           with
[build]           [
[build]               Sentence1=std::string,
[build]               Iterable=std::vector<std::string,std::allocator<std::string>>
[build]           ]

Here are my build informations:
MSVC 2019
C++20
CMake

I tried using a non-templated version, but I still get this error. Any idea on how to resolve this ?

Thank you

[maxbachmann]

Are you sure that you are already using the docs fix from: b23c9ad
Note that with C++20 it would be enough to use:

rapidfuzz::fuzz::CachedRatio scorer(query);

since I provide template deduction guides

[panosk]

Seeing your error message, you are indeed using the older example code.

[maxbachmann]

since I provide template deduction guides

Forgot to enable them on the msvc compiler, where __cplusplus does not return the correct result ...
Fixed in 0000f4e

[jokteur]

Thank you, the fix 0000f4e along with @maxbachmann answer work.