AbstractTrees parent child circular reference

New to Julia
4

Ah, that is an “artifact” of the way show is implemented. By trying to print the fields of any children, the parent is indeed referenced again, thus the output.

You can overload show(io::IO, n::TreeNode), i.e.

import Base: show

function show(io::IO, n::TreeNode)
   str_parent = isnothing(n.parent) ? "no parent" : "with parent"
   str_children = "$(length(children(n))) children"
   print(io, "TreeNode($str_parent, $(n.name), $(nodevalue(n)), $str_children)")
end

julia> current
TreeNode(no parent, root, 0, 1 children)

julia> tr
Tree(TreeNode[TreeNode(no parent, root, 0, 1 children)])
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