Method substring

src/fl/stl/string.cpp.hpp:151–159

// ======= SUBSTRING =======

string string::substring(fl::size start, fl::size end) const FL_NOEXCEPT {
    if (start == 0 && end == size()) return *this;
    if (start >= size()) return string();
    if (end > size()) end = size();
    if (start >= end) return string();
    string out;
    out.copy(c_str() + start, end - start);
    return out;
}

string string::substr(fl::size start, fl::size length) const FL_NOEXCEPT {
    // Handle `npos` / overflow: when `length == npos` the caller