Function printer_toStr

quest/src/core/printer.cpp:309–354

// type T can be precision decimal (independent of qreal) i.e. float, double, long double
template <typename T>
string printer_toStr(complex<T> num) {

    // precise 0 is rendered as a real integer
    if (std::real(num) == 0 && std::imag(num) == 0)
        return "0";

    // real complex-floats neglect imag component
    if (std::imag(num) == 0)
        return floatToStr(std::real(num));

    // imaginary complex-floats neglect real component entirely (instead of 0+3i)
    string realStr = (std::real(num) == 0)? "" : floatToStr(std::real(num));

    // scientific-notation real component (when followed by any imaginary component) gets brackets
    if (realStr.find('e') != string::npos)
        realStr = '(' + realStr + ')';

    // -1i is abbreviated to -i
    if constexpr (std::is_signed_v<T>)
        if (std::imag(num) == -1)
            return realStr + "-" + IMAGINARY_UNIT;

    // +1i is abbreviated to +i, although the sign is dropped if there's no preceeding real component
    if (std::imag(num) == 1)
        return realStr + ((std::real(num) == 0)? IMAGINARY_UNIT : ("+" + IMAGINARY_UNIT));

    // get imag component string but without sign
    string imagStr = floatToStr(std::imag(num), true);

    // scientific-notation components always get wrapped in paranthesis
    if (imagStr.find('e') != string::npos)
        imagStr = '(' + imagStr + ')';

    // negative imag components always get - sign prefix
    if (std::imag(num) < 0)
        imagStr = '-' + imagStr;

    // positive imag components only get + sign prefix if they follow a real component
    if (std::imag(num) > 0 && std::real(num) != 0)
        imagStr = '+' + imagStr;

    // all imag components end in 'i'
    imagStr += IMAGINARY_UNIT;

    return realStr + imagStr;
}


// explicitly instantiate all publicly passable types