Confusing return arrow in Model class to AddLessonCommand class.

[tandeshao]

Steps to reproduce:

1. Go to the developer's guide add temporary/recurring lesson section.

2. A sequence like the image below will be shown:

There is a return arrow from Model class to AddLessonCommand class when no method has been called. It is confusing and seems to be in the wrong place.

[soc-se-bot]

Team's Response

On its own, we would agree that the return-arrow would be confusing.

However, as this is a partial sequence-diagram, the user would be looking at this with reference to the main sequence-diagram (reproduced below),

When this is done, the return-arrow would make sense.

Additionally, the return-arrow has been included to make this partial sequence-diagram consistent with the other that is directly below it (reproduced below),

For this reason, we would be rejecting this bug report!

Items for the Tester to Verify

:question: Issue response

Team chose [response.Rejected]

• [x] I disagree

Reason for disagreement: I see what you mean, but the purpose of having ref frames is to abstract out the complexity that resides in a segment of the sequence diagram. That is, I should be able to understand the interactions in the main sequence diagram without needing to know the details of the interactions in the reference frame and vice versa. Observe how this is the case in an example provided in week 6 lecture notes (Reference frames).

Notice that the return arrow from the method markCellAt(x,y) (in the main sequence diagram) is located outside of the reference frame. By doing this, the main sequence diagram and the reference frame can be read separately from one another without having to know the interactions/complexities that reside in the other frame.

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