Module cow_and_paths 

Cow, PathBuf, OsString, and string collection conversions.

• Cow<'_, [T]> — owned copy of R native vectors
• Cow<'_, str> — owned copy of R character scalars
• PathBuf / OsString — from STRSXP via String intermediary
• HashSet<String> / BTreeSet<String> — string set conversions

Tradeoff

These TryFromSexp impls reject mismatched SEXPTYPEs — there is no looser coercion path for Cow / PathBuf / OsString. Raw Cow conversions own their data and may outlive the source. super::TryFromRoot supplies the borrowing path with a root-bound lifetime; generated wrappers use it for explicit Cow parameters.

Macros

impl_set_string_try_from_sexp 🔒

impl_string_wrapper_try_from_sexp 🔒

Generate TryFromSexp impls for types that are From<String> (scalar, Option, Vec, Vec<Option>). Used for PathBuf and OsString which delegate to String conversion.