Add CaseNode#branches

[marcandre]

I was surprised that IfNode#branches returns a array with a single item for if foo; else; end. I was expecting [nil, nil], not just [nil].

I mimicked this behavior for CaseNode as it seems natural to have this symmetry, but I wonder which is best. Anyone has an idea? cc/ @fatkodima

[fatkodima]

Symmetry is good, but it seems to me also that it should return [nil, nil] instead of just [nil] for provided example.

[marcandre]

There are different possibilities for IfNode#branches

1. always return the last else branch, even if it is only implicit:

if foo; end # => [nil, nil]
if foo; elsif bar; end # => [nil, nil, nil]

2. return the last else branch only if there's an explicit keyword

if foo; end # => [nil]
if foo; else; end # => [nil, nil]
if foo; elsif bar; end # => [nil, nil]
if foo; elsif bar; else; end # => [nil, nil, nil]

3. return the last else branch only if there keyword and some code in there [current]

if foo; else; end # => [nil]
if foo; else; 42; end # => [nil, s(:int, 42)]
if foo; elsif bar; else; end # => [nil, nil]
if foo; elsif bar; else; 42; end # => [nil, nil, s(:int, 42)]

I like #3 the least.

The same question exist for case and I'd like the answer to be the same... @fatkodima you prefer #2 or #1?

[fatkodima]

No. 2 seems the most logical to me.

[marcandre]

Thank you :-)

I made the tweak, and not a single spec fails, in rubocop-ast or rubocop... I put this as "potentially breaking" in the Changelog.