return String.format("and(%s, %s)", left, right);
    }

    @Override
    public boolean calculatePresence(ValueConsumer consumer) {
        try (EvaluationContext.ScopeContext ignored = openScope()) {
            if (!left.calculatePresence(consumer) || !right.calculatePresence(consumer)) {
                return false;
            }
        }

    @Override
    public ValueProducer getProducer() {
        try (EvaluationContext.ScopeContext context = openScope()) {
            return new OrElseValueProducer(context, left, right);
        }
    }

    @Override
    public boolean calculatePresence(ValueConsumer consumer) {
        try (EvaluationContext.ScopeContext ignored = openScope()) {
            return left.calculatePresence(consumer) || right.calculatePresence(consumer);
        }

        try (EvaluationContext.ScopeContext context = openScope()) {
            return backingProvider(context, consumer).calculatePresence(consumer);
        }
    }

    @Override
    protected Value<? extends S> calculateOwnValue(ValueConsumer consumer) {
        try (EvaluationContext.ScopeContext context = openScope()) {
            Value<? extends T> value = provider.calculateValue(consumer);

    public ValueProducer getProducer() {
        try (EvaluationContext.ScopeContext context = openScope()) {
            return new OrElseValueProducer(context, provider);
        }
    }

    @Override
    public ExecutionTimeValue<? extends T> calculateExecutionTimeValue() {
        try (EvaluationContext.ScopeContext ignored = openScope()) {
            ExecutionTimeValue<? extends T> value = provider.calculateExecutionTimeValue();

    @Override
    public ValueProducer getProducer() {
        try (EvaluationContext.ScopeContext ignored = openScope()) {
            return provider.getProducer();
        }
    }

    @Override
    public ExecutionTimeValue<? extends T> calculateExecutionTimeValue() {
        try (EvaluationContext.ScopeContext context = openScope()) {
            ExecutionTimeValue<? extends T> value = provider.calculateExecutionTimeValue();

    @Override
    public ValueProducer getProducer() {
        try (EvaluationContext.ScopeContext ignored = openScope()) {
            return provider.getProducer();
        }
    }

    @Override
    public ExecutionTimeValue<? extends OUT> calculateExecutionTimeValue() {
        try (EvaluationContext.ScopeContext context = openScope()) {
            ExecutionTimeValue<? extends IN> value = provider.calculateExecutionTimeValue();

        try (EvaluationContext.ScopeContext ignored = openScope()) {
            return provider.calculatePresence(consumer);
        }
    }

    @Override
    public ExecutionTimeValue<? extends OUT> calculateExecutionTimeValue() {
        try (EvaluationContext.ScopeContext context = openScope()) {
            ExecutionTimeValue<? extends IN> value = provider.calculateExecutionTimeValue();

            }
        }
        return null;
    }

    @Override
    protected Value<? extends T> calculateOwnValue(ValueConsumer consumer) {
        try (EvaluationContext.ScopeContext ignored = openScope()) {
            return Value.ofNullable(value.call());
        } catch (Exception e) {
            throw UncheckedException.throwAsUncheckedException(e);
        }
    }

        //  Without the safety net of the EvaluationContext, it can cause hard-to-debug exceptions.
        try (EvaluationContext.ScopeContext context = openScope()) {
            return getSupplier(context);
        }
    }

    public DefaultProperty<T> provider(Provider<? extends T> provider) {
        set(provider);
        return this;
    }

    }

    /**
     * Marks this provider as being evaluated until the returned scope is closed.
     *
     * @return the scope
     */
    protected EvaluationContext.ScopeContext openScope() {
        return EvaluationContext.current().open(this);
    }

    /**
     * An implementation for the toString method that is never called if the current provider is being evaluated.
     *