Function s4_get_slot 

pub unsafe fn s4_get_slot(
    obj: SEXP,
    slot_name: &str,
) -> Result<SEXP, REvalError>

Get the value of a named slot from an S4 object.

Uses R’s slot(obj, name) to access the slot value.

Safety

• obj must be a valid S4 SEXP with the named slot.
• Must be called from the R main thread.

Returns

• Ok(SEXP) with the slot value (unprotected).
• Err(REvalError) with R’s error if the slot doesn’t exist or another R error occurs.