handleOpBeforeCalculate method Null safety

  1. @override
void handleOpBeforeCalculate(
  1. Model<ProgramOperation> m,
  2. void opBeforeCalculate(
      )
    )
    override

    For many of the RCL operations on matrices, we need to take over stack lift, so we do the deferral on beforeCalculate rather than calc.

    Implementation

    @override
void handleOpBeforeCalculate(Model m, void Function() opBeforeCalculate) {
  final matrix = (m as Model15).matrices[matrixNumber];
  pressed(m, matrix);
  m.deferToButtonUp = DeferredFunction(m, () {
    if (!noStackLift) {
      // For RCL g <mat>, the column number is in X.  It might have come
      // from pressing a number key (and NOT enter), or it might have come
      // from some other operation.  We're about to consume the x and y
      // registers.  For RCL g <mat>, we should not do stack lift.
      opBeforeCalculate();
    }
    released(m, matrix);
  }).run;
}