We can use clang-tidy and its fixits to modernize code.

I think that we could also do this:

• Remove magic constants.
• Break huge functions in smaller ones with meaningful names.
• Take into consideration the compiler warnings and solve them as much as possible.
• Take the opportunity to improve the libraries' documentation.

(notes from KF6 sprint discussion)

Collected Experiences

std::variant -> poor for performance, not super nice api

std::optional -> used a lot in many places, but not in super-efficient places

std::function has compiler dependent implementation details, but nice to pass callbacks

there is a C++20 specific StringView that is not ABI compatible, do not use it in public API: https://doc.qt.io/qt-6/qutf8stringview.html

enum classes: Qt is not using them in public API

Guideline Ideas

--> at the end, this needs to go to the Library Policy

use std::optional instead of out parameters

QUrl & QString vs. std file system?

add overloads? --> compare to Qt's API approach

smart pointer handling --> should be compared to Qt usage

for non-QObjects, prefer smart pointers

enum classes yes/no?

support for structured bindings

use std::unique_ptr for d-pointers

Other Ideas:

we want to have std::expected but not want to wait for C++XX

try to get it into Qt

else, KCoreAddons

std::function has compiler dependent implementation details, but nice to pass callbacks

But it's rather heavy, how do we feel of templates for passing callbacks?

note to self: create actionable subtasks