object MultiTreeFlattener (source)
Flatten ParseTrees into multi-trees.
We escalate the children from a node to its parent if both the node and its parent have the same operator.
Example input:
CONCATENATION
/ | \
a CONCATENATION f
/ \
UNION e
/ \
b UNION
/ \
c d
Output:
CONCATENATION
/ | | \
a UNION e f
/ | \
b c d
fun <ImplementingTree : AbstractMultiTree<ImplementingTree>> flatten(tree: ImplementingTree): ImplementingTree
Flatten a given LogicalPlan recursively into a multi-tree. |