MODULE Showcase14;
// Session showcase: enumerations (literals in expressions / CASE /
// CONST), string content equality, Unicode (UCHAR literals, the Utf8
// codec, UTF-8 output), Conversions / RealIO, ProgramArgs and IOChan.
// Prints two lines and exits 42.
IMPORT SysIO, TextIO, Utf8, Conversions, RealIO, ProgramArgs, IOChan;

VAR ExitCode : INTEGER;
VAR n, m : INTEGER;
VAR out : IOChan.ChanId;
VAR s : ARRAY [0 .. 31] OF CHAR;
VAR cp : UCHAR;
VAR next : CARDINAL;
VAR x : REAL;

TYPE Color = (red, green, blue);
CONST Favourite = blue;

PROCEDURE Bump (points : INTEGER);
BEGIN
  n := n + points
END Bump;

BEGIN
  n := 0;

  (* enumerations: CASE label, ordinal ordering, CONST *)
  CASE Favourite OF
    red: n := 100
  | green: n := 100
  | blue: Bump(1)
  END;
  IF red < green THEN Bump(2) END;

  (* string content equality *)
  IF "abc" = "abc" THEN Bump(4) END;
  IF "abc" # "abd" THEN Bump(8) END;

  (* Unicode: strict decode of a UTF-8 literal back to a UCHAR *)
  IF Utf8.Decode("é", 0, cp, next) AND (UORD(cp) = 233) THEN Bump(16) END;

  (* ProgramArgs: run with no arguments *)
  IF ProgramArgs.ArgCount() = 0 THEN Bump(5) END;

  (* Conversions: integer and real round-trips *)
  IF Conversions.IntVal("-56", m) AND (m = -56) THEN Bump(3) END;
  IF Conversions.RealVal("3.5", x) AND (x = 3.5) THEN Bump(3) END;

  (* IOChan demo goes to stderr (stdio buffering would otherwise
     reorder it against the unbuffered shim writes) *)
  out := IOChan.StdErrChan();
  IOChan.WriteString(out, "iochan: showcase14 evaluating");
  IOChan.WriteLn(out);

  (* stdout: summary line, then REAL + UTF-8 via TextIO *)
  SysIO.Write("showcase14 n=");
  Conversions.IntToStr(n, s);
  SysIO.Write(s);
  SysIO.WriteLn;

  RealIO.WriteReal(3.5);
  TextIO.WriteString(" ");
  TextIO.UWriteString(U"ok ✓");
  TextIO.WriteLn;

  ExitCode := n
END Showcase14.