M2compiler-V3/compiler/tests/showcase19.mod

MODULE Showcase19;
// Session showcase: class init body + sibling method calls.
//
// The Accumulator class sets a global scale factor in its BEGIN body
// (run once at startup); its methods call each other by bare name --
// chains of sibling calls on THIS.
// Expected ExitCode: 42.
IMPORT TextIO, Conversions;

VAR scale : INTEGER;               (* set by Accumulator's init body *)

TYPE
  CLASS Accumulator;
    total : INTEGER;
    PROCEDURE Init(v : INTEGER);
    PROCEDURE Add(v : INTEGER);
    PROCEDURE AddScaled(v : INTEGER);      (* sibling: Add *)
    PROCEDURE AddPair(a, b : INTEGER);     (* sibling: AddScaled *)
    PROCEDURE Value() : INTEGER;
  END Accumulator;

CLASS IMPLEMENTATION Accumulator;
  PROCEDURE Init(v : INTEGER);
  BEGIN total := v END Init;

  PROCEDURE Add(v : INTEGER);
  BEGIN total := total + v END Add;

  PROCEDURE AddScaled(v : INTEGER);
  BEGIN Add(v * scale) END AddScaled;      (* sibling call on THIS *)

  PROCEDURE AddPair(a, b : INTEGER);
  BEGIN AddScaled(a); AddScaled(b) END AddPair;

  PROCEDURE Value() : INTEGER;
  BEGIN RETURN total END Value;
BEGIN
  scale := 10                              (* class init body *)
END Accumulator;

VAR ExitCode : INTEGER;
VAR acc : Accumulator;
VAR line, num : ARRAY [0 .. 63] OF CHAR;

BEGIN
  ExitCode := 0;

  acc.Init(0);
  acc.AddPair(2, 2);            (* AddScaled -> Add: +20 +20 = 40 *)
  acc.Add(2);                   (* +2 = 42 *)

  Conversions.IntToStr(acc.Value(), num);
  line := "showcase19 total=" + num;
  TextIO.WriteString(line);
  TextIO.WriteLn;

  IF acc.Value() = 42 THEN ExitCode := 42 ELSE ExitCode := 1 END
END Showcase19.