Function Rf_list4 

pub unsafe fn Rf_list4(s: SEXP, t: SEXP, u: SEXP, v: SEXP) -> SEXP

Build a pairlist with 4 elements.

Rust equivalent of R’s inline Rf_list4(s, t, u, v).

Safety

• All SEXPs must be valid
• Must be called from R’s main thread
• Result must be protected from GC