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ASF GitHub Bot commented on TINKERPOP-967: ------------------------------------------ Github user dkuppitz commented on a diff in the pull request: https://github.com/apache/tinkerpop/pull/876#discussion_r202114064 --- Diff: gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/traverser/B_LP_NL_O_P_S_SE_SL_Traverser.java --- @@ -0,0 +1,156 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ +package org.apache.tinkerpop.gremlin.process.traversal.traverser; + +import org.apache.commons.collections.map.ReferenceMap; +import org.apache.tinkerpop.gremlin.process.traversal.Step; +import org.apache.tinkerpop.gremlin.process.traversal.traverser.util.LabelledCounter; + + +import java.util.Iterator; +import java.util.Stack; + +public class B_LP_NL_O_P_S_SE_SL_Traverser<T> extends B_LP_O_P_S_SE_SL_Traverser<T> { + + protected Stack<LabelledCounter> nestedLoops; + protected ReferenceMap loopNames = null; --- End diff -- Just asking for a comment here: Why can this not be a simple `HashMap<String, LabelledCounter>`? This would save you the class casting later on and you wouldn't have to register a new class for the Gryo serializer. > Support nested-repeat() structures > ---------------------------------- > > Key: TINKERPOP-967 > URL: https://issues.apache.org/jira/browse/TINKERPOP-967 > Project: TinkerPop > Issue Type: Improvement > Components: process > Affects Versions: 3.1.0-incubating > Reporter: Marko A. Rodriguez > Assignee: Marko A. Rodriguez > Priority: Major > > All the internal plumbing is staged for this to happen, we just haven't gone > all the way. In short, a {{NESTED_LOOP}} traverser has an internal > {{loopStack}} where {{repeat(repeat())}} will have a {{loopStack}} of two. > The {{it.loops()}} checks of the internal repeat will always check the top of > the stack and when its done repeating will delete its counter off the top of > the stack. > [~dkuppitz]'s work on {{LoopStep}} will be backwards compatible. In > {{RepeatStep}} we will support: > {code} > repeat('a',out('knows').repeat('b',out('parent'))) > {code} > and thus, things like {{loops('a')}} as well as {{times('a',2)}}. Note that > naming the loop stack will be a super rare case as most people will just > assume standard nested looping semantics with a push/pop stack. -- This message was sent by Atlassian JIRA (v7.6.3#76005)