MODULE Showcase20;
// Session showcase: array and record constructors (GNU Modula-2).
//
//   * a CHAR-array CONST from a constructor;
//   * a CARDINAL-array CONST using the `expr BY n` repeat form;
//   * a static record constructor (a nested array-from-string field
//     and an inlined nested record field);
//   * a runtime record constructor (fields from variables);
//   * a runtime array constructor (elements from variables).
//
// Expected ExitCode: 42.
IMPORT TextIO, Conversions;

TYPE
  Name   = ARRAY [0..7] OF CHAR;
  Triple = ARRAY [0..2] OF CARDINAL;
  Date   = RECORD y, m, d : CARDINAL END;
  Person = RECORD name : Name; born : Date END;

CONST
  Greet = Name   { 'H','e','l','l','o','!','!','!' };
  Base  = Triple { 7, 7 BY 2 };          (* the repeat form: 7, 7, 7 *)

VAR
  p, q  : Person;
  a, b  : Triple;
  i     : CARDINAL;
  total : CARDINAL;
  msg   : ARRAY [0 .. 63] OF CHAR;
  num   : ARRAY [0 .. 15] OF CHAR;
  ExitCode : INTEGER;

BEGIN
  (* static record constructor: string field + inlined nested record *)
  p := Person { "Modula", Date { 1980, 5, 3 } };

  (* runtime record constructor: every field is a runtime value *)
  i := p.born.m;                          (* 5 *)
  q := Person { "Runtime", Date { i, i + 1, i + 2 } };

  (* runtime array constructor: elements from variables *)
  a := Triple { i, i + 1, i + 2 };        (* 5, 6, 7 *)
  b := Triple { Base[0], Base[1], Base[2] };

  total := 0;
  total := total + Base[0] + Base[1] + Base[2];   (* 7+7+7  = 21 *)
  total := total + a[0] + a[1] + a[2];            (* 5+6+7  = 18 *)
  total := total + p.born.d;                      (* 3      = 42 *)

  Conversions.CardToStr(total, num);
  msg := "showcase20 total=" + num;
  TextIO.WriteString(msg);
  TextIO.WriteLn;

  IF (total = 42)
     AND (Greet[0] = 'H') AND (Greet[7] = '!')
     AND (p.name[0] = 'M') AND (p.born.y = 1980)
     AND (q.name[0] = 'R') AND (q.born.d = 7)
     AND (b[0] = 7) AND (b[2] = 7)
  THEN ExitCode := 42 ELSE ExitCode := 1 END
END Showcase20.