beman::optional::optional<T&>::transform

Applies a function to the stored value if there is one.

Synopsis

template<class F>
constexpr
optional<std::invoke_result_t<F, T&>>
transform(F&& f) const;

Description

The return type is the same as

{std::invoke_result_t<F, T&>}, but wrapped in an optional.

Return Value

optional<std::invoke_result_t<F, T&>>