gremlin step for building trees from a graph traversal

treeSideEffect

// tree building gremlin defined step
// toTree()
// Redouane Lakrache, r3d0ne@gmail.com

toTree = {
	current = [id:0, children:[]]; //init tree head
	tree = [current]
	parents = []; //tracking current branch
	i = i + 1;
	def depth = i; //setp call order
	_()
	.sideEffect{
		def parents_length = parents.size();
		def t = [:];
		t.v = it;
		t.children = [];
		if(depth == 1) {
			parents = [];
			current = tree[0]
			current.children.add(t);
		}
		else {
			if(parents_length == depth) {
				parents = parents[0..depth - 2];
				parents[-1].children.add(t);
				current = parents[-1];
			}
			if(parents_length < depth) {
				parents[-1].children.add(t);
				current = t;
			}
			if(parents_length > depth) {
				parents = parents[0..depth -2];
				current = parents[-1];
				current.children.add(t);
			}
		}
		parents.add(t);
	}
}

Gremlin.defineStep('toTree', [Vertex, Pipe], toTree)

i = 0;
tree = [];

g = TinkerGraphFactory.createTinkerGraph()