    /*
        pybind11/options.h: global settings that are configurable at runtime.

        Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>

        All rights reserved. Use of this source code is governed by a
        BSD-style license that can be found in the LICENSE file.
    */

    #pragma once

    #include "detail/common.h"

    PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)

    class options {
    public:
        // Default RAII constructor, which leaves settings as they currently are.
        options() : previous_state(global_state()) {}

        // Class is non-copyable.
        options(const options &) = delete;
        options &operator=(const options &) = delete;

        // Destructor, which restores settings that were in effect before.
        ~options() { global_state() = previous_state; }

        // Setter methods (affect the global state):

        options &disable_user_defined_docstrings() & {
            global_state().show_user_defined_docstrings = false;
            return *this;
        }

        options &enable_user_defined_docstrings() & {
            global_state().show_user_defined_docstrings = true;
            return *this;
        }

        options &disable_function_signatures() & {
            global_state().show_function_signatures = false;
            return *this;
        }

        options &enable_function_signatures() & {
            global_state().show_function_signatures = true;
            return *this;
        }

        options &disable_enum_members_docstring() & {
            global_state().show_enum_members_docstring = false;
            return *this;
        }

        options &enable_enum_members_docstring() & {
            global_state().show_enum_members_docstring = true;
            return *this;
        }

        // Getter methods (return the global state):

        static bool show_user_defined_docstrings() {
            return global_state().show_user_defined_docstrings;
        }

        static bool show_function_signatures() { return global_state().show_function_signatures; }

        static bool show_enum_members_docstring() {
            return global_state().show_enum_members_docstring;
        }

        // This type is not meant to be allocated on the heap.
        void *operator new(size_t) = delete;

    private:
        struct state {
            bool show_user_defined_docstrings = true; //< Include user-supplied texts in docstrings.
            bool show_function_signatures = true;     //< Include auto-generated function signatures
                                                      //  in docstrings.
            bool show_enum_members_docstring = true;  //< Include auto-generated member list in enum
                                                      //  docstrings.
        };

        static state &global_state() {
            static state instance;
            return instance;
        }

        state previous_state;
    };

    PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)