Listing:

    1  MODULE Showcase4;
    2  
    3  (* Step-11 tour: DEFINITION/IMPLEMENTATION library, IMPORT + FROM,
    4     qualified and unqualified use, lib init before program body. *)
    5  
    6  FROM S4L IMPORT Pair, Add;
    7  VAR p, q : Pair;
    8  VAR w : INTEGER;
    9  VAR total : INTEGER;
   10  VAR ExitCode : INTEGER;
   11  
   12  BEGIN
   13    total := 0;
   14    WriteString("show4");
   15    w := S4L.n;
   16    S4L.Bump(w);
   17    S4L.n := w;
   18    total := total + S4L.n;
   19    p.a := 1; p.b := 2;
   20    q := p;
   21    total := total + q.a + q.b;
   22    total := total + Add(S4L.base, 5);
   23    total := total + S4L.base;
   24    WriteInt(total);
   25    ExitCode := total
   26  END Showcase4.

    0 errors