std::ranges::transform

cppreference.com

Example

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Foo: @struct type = {
    bar: char;
}

main: () = {
    s: std::string = ("hello");
    op:= :(c: char) unsafe_narrow<char>(std::toupper(c));

    ranges: namespace == std::ranges;

    // uppercase the string in-place
    ranges::transform(s.begin(), s.end(), s.begin(), op);

    ordinals: std::vector<std::size_t> = ();
    // convert each char to size_t
    ranges::transform(s, std::back_inserter(ordinals),
                      :(c: char) c as std::size_t);

    std::cout << "(s)$:";
    for ordinals do (ord) {
        std::cout << " (ord)$";
    }

    // double each ordinal
    ranges::transform(ordinals, ordinals, ordinals.begin(), std::plus());

    std::cout << '\n';
    for ordinals do (ord) {
        std::cout << "(ord)$ ";
    }
    std::cout << '\n';

    f: const std::vector = (
        :Foo=('h'),
        :Foo=('e'),
        :Foo=('l'),
        :Foo=('l'),
        :Foo=('o'));

    result: std::string = ();
    // project, then uppercase
    ranges::transform(f, std::back_inserter(result), op, Foo::bar&);
    std::cout << result << '\n';
}

Output

HELLO: 72 69 76 76 79
144 138 152 152 158 
HELLO