error: no match for 'operator!='

[MeastroZI]

for this code

#include <sourcemeta/jsontoolkit/jsonl.h>
#include <cassert>
#include <sstream>
#include <iostream>

int main()
{
    std::istringstream stream{
        "{ \"foo\": 1 }\n{ \"bar\": 2 }\n{ \"baz\": 3 }"};

    for (const auto &document : sourcemeta::jsontoolkit::JSONL{stream})
    {
        assert(document.is_object());
        sourcemeta::jsontoolkit::prettify(document, std::cout);
        std::cout << '\n';
    }
}

I am getting this error

error: no match for 'operator!=' (operand types are 'sourcemeta::jsontoolkit::JSONL::const_iterator' {aka 'sourcemeta::jsontoolkit::ConstJSONLIterator'} and 'sourcemeta::jsontoolkit::JSONL::const_iterator' {aka 'sourcemeta::jsontoolkit::ConstJSONLIterator'})
   12 |     for (const auto &document : sourcemeta::jsontoolkit::JSONL{stream})
      |                                          

GCC version : 11.4.0

[MeastroZI]

But tests for this are running without throwing errors, i dont know why ?
@jviotti ?

[jviotti]

@MeastroZI On what OS are you on?

• Can you try compiling your example with another compile? I.e. LLVM or MSVC? Do you get an issue there too?
• With GCC 11.4.0 on whatever OS you are on, does the JSON Toolkit test suite compile and run well, or do you get failures?
• How are you compiling the example above, precisely? i.e. you can show the commands you are using?

[MeastroZI]

Ah, it seems the issue isn't with the compiler itself, but rather with the default C++ standard, which is set to 17 on my system running Ubuntu 22

here is the edited CMakeList.txt which work fine

cmake_minimum_required(VERSION 3.22)
project(HelloWorld)
set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_EXTENSIONS OFF)

add_executable(hello hello.cpp)
add_subdirectory(deps/jsontoolkit)


target_link_libraries(hello PUBLIC sourcemeta::jsontoolkit::json)
target_link_libraries(hello PUBLIC sourcemeta::jsontoolkit::jsonschema)
target_link_libraries(hello PUBLIC sourcemeta::jsontoolkit::jsonpointer)
target_link_libraries(hello PUBLIC sourcemeta::jsontoolkit::jsonl)

[jviotti]

Interesting! A more backwards compatible approach would be to use the spaceship operator instead of implementing specific ones like we do now. I believe that would make it work on C++17 too. See #509

[MeastroZI]

Hmm, and one more thing: the contains method for maps is not available for the standard version less than 20. So, I'm also encountering an error for that

[jviotti]

Yep. The documentation (https://jsontoolkit.sourcemeta.com/) clarifies that C++20 or later is expected. Probably a lot more would be needed to make it work on C++17 which is likely not worth it