[Moose-dev] Roassal RTAttachPoint inverted

Hi Alex,

I've noticed that with addition of DoubleArrowedLine you've also added concept of "inverted" to attach points. This seems really strange from the perspective that all methods startingPointOf: and endingPointOf: are identical only with swapped ifTrue:/ifFalse:

for example ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ startingPointOf: anEdge ^ (inverted ifTrue:[anEdge to] ifFalse:[anEdge from]) position endingPointOf: anEdge ^ (inverted ifTrue: [anEdge from] ifFalse: [anEdge to]) position ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

this is harder to read and more error-prone than ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ startingPointOf: anEdge ^ anEdge from position endingPointOf: anEdge ^ anEdge to position ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ plus there is code duplication. And this is just the simplest attach point.

Since I should also add "inverted" to my attach points that are in Roassal (RTRectangleAttachPoint, ...) maybe the actual computation should be delegated?

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ RTAttachPoint>>startingPointOf: anEdge ^ inverted ifTrue: [ self basicEndingPointOf: anEdge ] ifFalse: [ self basicStartingPointOf: anEdge ]

RTAttachPoint>>endingPointOf: anEdge ^ inverted ifTrue: [ self basicStartingPointOf: anEdge ] ifFalse: [ self basicEndingPointOf: anEdge ]

RTAttachPoint>>basicStartingPointOf: anEdge ^ self subclassResponsibility

RTAttachPoint>>basicEndingPointOf: anEdge ^ self subclassResponsibility ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This also will not break current implementation but it will give opportunity to improve them.

And if there was a situation where the implementation would be actually different for inverted (and not just swapped values), than you could still just implement startingPointOf:/endingPointOf:

Thanks, Peter