Get a numeric id for this node that is unique.
Within a given syntax tree, no two nodes have the same id. However, if a new tree is created based on an older tree, and a node from the old tree is reused in the process, then that node will have the same id in both trees.
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Get a numeric id for this node that is unique.
Within a given syntax tree, no two nodes have the same id. However, if a new tree is created based on an older tree, and a node from the old tree is reused in the process, then that node will have the same id in both trees.