MODULE Showcase16;
// Session showcase: variant records, UString assignment to an
// ARRAY OF UCHAR, and Files layered on IOChan.
//
// It builds a Shape variant record, encodes a Unicode label into a
// UCHAR array, writes both through a Files handle (itself an IOChan
// channel), reads the line back and prints a summary.
// Expected ExitCode: 42.
IMPORT Files, TextIO, Strings, Conversions;

TYPE
  Kind = (circle, square, rect);
  Shape = RECORD
    id : INTEGER;
    CASE k : Kind OF
      circle : radius : INTEGER;
    | square : side : INTEGER;
    | rect   : w, h : INTEGER;
    END;
  END;

VAR ExitCode : INTEGER;
VAR f : Files.File;
VAR name, line : ARRAY [0 .. 63] OF CHAR;
VAR label : ARRAY [0 .. 7] OF UCHAR;
VAR s : Shape;
VAR total : INTEGER;

BEGIN
  ExitCode := 0;

  (* variant record: the rect branch's fields overlay one slot *)
  s.id := 3;
  s.k := rect;
  s.w := 20;
  s.h := 22;                               (* shares the slot with s.w *)
  IF s.id = 3 THEN ExitCode := ExitCode + 1 ELSE ExitCode := 90 END;
  IF s.k = rect THEN ExitCode := ExitCode + 2 ELSE ExitCode := 91 END;
  IF s.h = 22 THEN ExitCode := ExitCode + 4 ELSE ExitCode := 95 END;
  total := s.id * s.h - 24;                (* 3*22 - 24 = 42 *)

  (* UString assignment into a UCHAR array (content copy) *)
  label := U"ok✓";
  IF label[0] = U'o' THEN ExitCode := ExitCode + 8 ELSE ExitCode := 92 END;
  IF label[2] = U'✓' THEN ExitCode := ExitCode + 16 ELSE ExitCode := 93 END;

  (* write through Files (an IOChan channel), then read back *)
  Strings.Assign("gen_ssa/_showcase16.txt", name);
  f := Files.OpenWrite(name);
  Files.WriteString(f, "id=");
  Files.WriteInt(f, s.id);
  Files.WriteString(f, " total=");
  Files.WriteInt(f, total);
  Files.WriteLn(f);
  Files.Close(f);

  f := Files.OpenRead(name);
  Files.ReadString(f, line);
  IF line = "id=3 total=42" THEN
    ExitCode := ExitCode + 32
  ELSE ExitCode := 94 END;
  Files.Close(f);

  TextIO.WriteString("showcase16: ");
  TextIO.WriteString(line);
  TextIO.WriteLn;

  IF ExitCode = 63 THEN ExitCode := total END      (* 42 *)
END Showcase16.