cpp23.md

CPP 23

• New language features
  • if with consteval
  • Misc improvements
• New library features
  • monadic optional
  • expected
  • Ranges improvements
  • Other improvements
• Some of the references

New language features

if with consteval

If statememnt can be written with consteval keyword to executed different code depending whether if function is executed during compile time or during run-time.

constexpr bool is_constant_evaluated() noexcept {
    if consteval { return true; }
    else { return false; }
}

constexpr bool is_runtime_evaluated() noexcept {
    if not consteval { return true; }
    else { return false; }
}

Misc improvements

• Init statement in range based for loop can be alias declaration

New library features

monadic optional

Optional has 3 methods add to enable functional style programming:

• and_then
• or_else
• transform

expected

Error handling type similar to optional.

Ranges improvements

• std::ranges::starts_with and std::ranges::ends_with is added
• std::ranges::shift_left and std::ranges::shift_right is added
• std::ranges::fold_left and std::ranges::fold_right is added
• std::ranges::iota is added
• std::ranges::to is added
• std::ranges::views::zip is added
• std::ranges::views::zip_transform is added
• std::ranges::views::adjacent is added
• std::ranges::views::adjacent_transform is added
• std::ranges::views::join_with is added
• std::ranges::views::slide is added
• std::ranges::views::chunk is added
• std::ranges::views::chunk_by is added
• std::ranges::views::repeat is added
• std::ranges::views::cartesian_product is added
• std::ranges::views::as_const is added
• std::ranges::views::as_rvalue is added
• std::ranges::views::stride is added

Other improvements

• access currently executing stack trace has been added
• bind_back added for wrapping a function with last parameters specified
• compatibility macro _Atomic provided such that _Atomic(T) is identical to atomic<T>
• more functions (erase, extract, insert, insert_or_assign, operator[], bucket) aware of transparent/heterogenous searching
• garabage collector related basics introduced in C++11 are removed
• string and string_view have contains method added

Some of the references

• CPP Reference