Module strings 

String conversions — STRSXP requires special handling via STRING_ELT.

R stores strings as STRSXP (vector of CHARSXP). Each element requires STRING_ELT + R_CHAR to extract, unlike numeric vectors which expose a contiguous data pointer.

Covers: &str, String, char, Option<&str>, Option<String>, Vec<String>, Vec<&str>, Box<[String]>.