MODULE Showcase21;
// Tour of three features added this step:
//
//   * result suffixes — components applied to a function-call result
//     (GetRec()^.field, GetArr()^[i]);
//   * PIM coroutines from SYSTEM — PROCESS / NEWPROCESS / TRANSFER,
//     two coroutines ping-pong five times and hand control back;
//   * ISO/gm2 standard library — RealStr (RealToFixed), LongMath
//     (sqrt/round), WholeStr (CardToStr) and DynamicStrings
//     (InitString/ConCat/CopyOut) build the output label.
//
// Writes "showcase21 total=42"; expected ExitCode: 42.
IMPORT StrIO, WholeStr, RealStr, LongMath, DynamicStrings;
FROM DynamicStrings IMPORT String;
FROM SYSTEM IMPORT ADDRESS, PROCESS, NEWPROCESS, TRANSFER, ADR;

TYPE
  Rec    = RECORD a, b : INTEGER END;
  RecPtr = POINTER TO Rec;
  Arr    = ARRAY [0..3] OF INTEGER;
  ArrPtr = POINTER TO Arr;

VAR ExitCode : INTEGER;
VAR r : RecPtr;
VAR s : ArrPtr;
VAR total : INTEGER;
VAR x : REAL;
VAR hits : CARDINAL;

VAR ping, pong, exits : PROCESS;
VAR ws1, ws2 : ARRAY [0..65535] OF CHAR;

VAR num, label, out : ARRAY [0..63] OF CHAR;
VAR ds : String;

PROCEDURE GetRec () : RecPtr;
BEGIN RETURN r END GetRec;

PROCEDURE GetArr () : ArrPtr;
BEGIN RETURN s END GetArr;

PROCEDURE Ping;
BEGIN
  LOOP
    TRANSFER(ping, pong)
  END
END Ping;

PROCEDURE Pong;
BEGIN
  LOOP
    INC(hits);
    IF hits >= 5 THEN TRANSFER(pong, exits) END;
    TRANSFER(pong, ping)
  END
END Pong;

BEGIN
  ExitCode := 0;

  (* --- result suffixes --- *)
  NEW(r); NEW(s);
  r^.a := 40; r^.b := 2;
  s^[0] := 1; s^[1] := 2; s^[2] := 2; s^[3] := 4;
  IF GetRec()^.a + GetRec()^.b = 42 THEN
    ExitCode := ExitCode + 1
  ELSE ExitCode := 100 END;
  IF GetArr()^[1] + GetArr()^[2] = 4 THEN
    ExitCode := ExitCode + 2
  ELSE ExitCode := 100 END;

  total := 40;
  total := total + GetArr()^[1] + GetArr()^[2];   (* 44 *)
  total := total - GetRec()^.b;                    (* 42 *)

  (* --- ISO/gm2 library --- *)
  RealStr.RealToFixed(42.0, 0, num);               (* "42" *)
  x := LongMath.sqrt(1764.0);                      (* 42.0 *)
  IF (num[0] = "4") AND (num[1] = "2") AND
     (LongMath.round(x) = 42) THEN
    ExitCode := ExitCode + 4
  ELSE ExitCode := 100 END;

  (* --- coroutines --- *)
  NEWPROCESS(Ping, ADR(ws1), 65536, ping);
  NEWPROCESS(Pong, ADR(ws2), 65536, pong);
  TRANSFER(exits, ping);
  IF hits = 5 THEN ExitCode := ExitCode + 8 ELSE ExitCode := 100 END;

  (* --- output line via DynamicStrings + WholeStr --- *)
  WholeStr.CardToStr(VAL(CARDINAL, total), num);
  ds := DynamicStrings.InitString("showcase21 total=");
  ds := DynamicStrings.ConCat(ds, DynamicStrings.InitString(num));
  DynamicStrings.CopyOut(out, ds);
  StrIO.WriteString(out);
  StrIO.WriteLn;

  IF ExitCode = 15 THEN ExitCode := 42 END
END Showcase21.