yomm2

_{defined in <yorel/yomm2/core.hpp>, also provided by <yorel/yomm2/keywords.hpp>, <yorel/yomm2.hpp>}

error_handler_type set_error_handler(error_handler_type handler);

All errors are reported via an indirect call to a handler, passing it a std::variant that identifies the specific error. The handler can be set to a user-defined function with set_error_handler. The library calls abort() immediately after calling the handler, but the handler can prevent program termination by throwing an exception. The default handler writes an error message to stderr in debug mode.

set_error_handler returns the previous handler.

Example

#include <stdexcept>
#include <yorel/yomm2/keywords.hpp>

struct Animal {
    virtual ~Animal() {
    }
};

struct Dog : Animal {};

register_classes(Animal, Dog);

declare_method(void, kick, (virtual_<Animal&>));

using namespace yorel::yomm2; // for brevity

error_handler_type next_error_handler;

void no_definition_handler(const error_type& ev) {
    if (auto error = std::get_if<resolution_error>(&ev)) {
        if (error->status == resolution_error::no_definition) {
            throw std::runtime_error("not defined");
        }
    }

    next_error_handler(ev);
}

BOOST_AUTO_TEST_CASE(ref_set_error_handler_example) {
    next_error_handler = set_error_handler(no_definition_handler);
    update();

    try {
        Dog snoopy;
        kick(snoopy);
    } catch (const std::runtime_error& error) {
        BOOST_TEST(error.what() == "not defined");
        return;
    }

    BOOST_FAIL("did not throw");
}

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