[Idea] Use Raii + operator bool instead of begin/end functions

[light-and-ray]

Hello. I'm exploring your library. And it looks very neat! But I don't see the need in End... functions: ImGui::EndMenu, ImGui::EndMenuBar, etc

if (ImGui::BeginMenuBar())
{
    if (ImGui::BeginMenu("File"))
    {
        if (ImGui::MenuItem("Open..", "Ctrl+O")) { /* Do stuff */ }
        if (ImGui::MenuItem("Save", "Ctrl+S"))   { /* Do stuff */ }
        if (ImGui::MenuItem("Close", "Ctrl+W"))  { my_tool_active = false; }
        ImGui::EndMenu();
    }
    ImGui::EndMenuBar();
}

Instead of returning bool from ImGui::BeginMenu, it can return an object with overridden operator bool, and in the destructor it calls ImGui::EndMenu()

Here is a quick example:

class RaiiMenu
{
public:
    template <typename ...Params>
    RaiiMenu(Params&&... params)
    {
        m_returnedValue = ImGui::BeginMenu(std::forward<Params>(params)...);
    }
    ~RaiiMenu()
    {
        if (m_returnedValue) {
            ImGui::EndMenu();
        }
    }
    operator bool() const { return m_returnedValue; }
private:
    bool m_returnedValue = false;
};

I'm sorry if this idea is banal and was discussed many times 😅 I haven't found a similar discussion. But the fact that you have to write end functions looks out of place, so if it has never been considered, it worth consider this.. Maybe there are some use cases for begin/end functions in more complex scenarios, where you need to call them earlier, or begin menu earlier. But an alternative have these Raii equivalents would be very neat

It also can be generalized with a class template:

template<auto BeginFunction, auto EndFunction>
class RaiiBeginEnd
{
public:
    template <typename ...Params>
    RaiiBeginEnd(Params&&... params)
    {
        m_returnedValue = BeginFunction(std::forward<Params>(params)...);
    }
    ~RaiiBeginEnd()
    {
        if (m_returnedValue) {
            EndFunction();
        }
    }
    operator bool() const { return m_returnedValue; }
private:
    bool m_returnedValue = false;
};

using RaiiMenu = RaiiBeginEnd<ImGui::BeginMenu, ImGui::EndMenu>;
using RaiiListBox = RaiiBeginEnd<ImGui::BeginListBox, ImGui::EndListBox>;
// ... etc

[ocornut]

Please don’t use Discussions for this, it is clearly highlighted in many locations.

I'm sorry if this idea is banal and was discussed many times 😅 I haven't found a similar discussion.

I typed “raii” into the search box and immediately found for #2096 for discussions about Raii.

[light-and-ray]

Sorry, I searched only in discussions. My mistake

[ocornut]

No worries. I’m trying to keep discussions together. Though that raii topic has become daunting tbh.