2009/1/13 Hilaire Fernandes <hilaire@ofset.org>:

I need to write a DoubleLinkedList, checking for LinkedList I saw

add: link after: otherLink

"Add otherLink after link in the list. Answer aLink."

| savedLink | lastLink == otherLink ifTrue: [^ self addLast: link]. savedLink := otherLink nextLink. otherLink nextLink: link. link nextLink: savedLink. ^link.

Why is savedLink needed ?

Why not: lastLink == otherLink ifTrue: [^ self addLast: link]. link nextLink: otherLink nextLink. otherLink nextLink: link. ^link.

Are there any hidden reason I don't see?

isn't a DoubleLinkedList means that there should be not only next, but prev as well? then, if nextLink: implemented as following (i don't have sources): nextLink: aLink next := aLink. aLink prev: self then you should use savedLink to avoid losing a correct prev link.

-- http://blog.ofset.org/hilaire

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