Function isws

inst/include/Rcpp/sugar/functions/strings/trimws.h:36–38

NB: std::isspace is not used because it also counts '\f' and '\v' as whitespace, whereas base::trimws only checks for ' ', '\t', '\r', and '\n' */

    '\f' and '\v' as whitespace, whereas base::trimws only
    checks for ' ', '\t', '\r', and '\n'  */
inline bool isws(const char c) {
    return c == ' ' || c == '\t' || c == '\n' || c == '\r';
}

inline const char* trim_left(const char* str) {
    if (!str) {