Add BeginKeywordNode for kwbegin nodes

[dvandersluis]

Allows for kwbegin nodes to not need destructuring, as in rubocop/rubocop#13426.

[dvandersluis]

@marcandre @bquorning this isn't quite as straightforward as I originally thought. 😅

When the body of a begin is multiple lines, they are expressed as multiple items within the node:

$ ruby-parse -e '
begin
  foo
  bar
end
'
(kwbegin
  (send nil :foo)
  (send nil :bar))

Rubocop seems to act as if the kwbegin body is just the first one, but should it return an array of nodes instead?

I also added test cases for begin...rescue...ensure...end but I don't have it fully working yet.

[dvandersluis]

I've also gone back and forth on if this should be BeginNode, BeginKeywordNode, or KwbeginNode. I've landed on BeginKeywordNode (because begin nodes also exist and could theoretically have a Node class one day) but let me know your thoughts.

[marcandre]

Without much thought, I'd say body should be an array, and name should be KeywordBeginNode.

[dvandersluis]

name should be KeywordBeginNode.

Ah yes of course, a fourth option I didn't consider 😂 I'll change it up this afternoon.

[dvandersluis]

Maybe body should be the kwbegin node itself when there are multiple nodes? I'm not really sure why parser doesn't create a begin node around the body otherwise. It does when there is an ensure or rescue:

ruby-parse -e '
begin
  foo
  bar
ensure
  baz
end
'
(kwbegin
  (ensure
    (begin
      (send nil :foo)
      (send nil :bar))
    (send nil :baz)))

ruby-parse -e '
begin
  foo
  bar
rescue
  baz
end
'
(kwbegin
  (rescue
    (begin
      (send nil :foo)
      (send nil :bar))
    (resbody nil nil
      (send nil :baz)) nil))

I think it would probably make sense to treat the kwbegin as if it's a begin node then. What do you think?

[marcandre]

Looks good to me 👍

[dvandersluis]

@marcandre do you want me to do this as a separate PR, or create a separate changelog entry for it pointing to this PR?

[marcandre]

Either work, your choice 😄

[dvandersluis]

Updated.

[marcandre]

Great, thanks. Released as 1.35

[dvandersluis]

Thanks @marcandre!