Uh…. First select() is already taken and by() is always a by()-modulator…… :/ Even with that, we still can't fix the backwards compatibility issue as we can't deprecate out the second by(). How do you say "if the second by() is applied, its Deprecated?" Perhaps Logger.WARN or something.. Dunno, sorta odd.
Marko. http://markorodriguez.com On Oct 6, 2015, at 3:26 PM, Ran Magen <[email protected]> wrote: > How about changing the second 'by' to a more indicative name (could > 'select' work?)? > > That way we could improve on the name (which always had me confused), and > leave the second+third 'by's as an indication to use the old > implementation... > > On יום ד׳, 7 באוק׳ 2015 at 0:18 Marko Rodriguez <[email protected]> > wrote: > >> Hello everyone (and the NSA -- Kuppitz did it), >> >> This is regarding this ticket: >> https://issues.apache.org/jira/browse/TINKERPOP3-866 >> >> In group_step_2/ branch we have a new implementation of GroupStep. Here is >> an example: >> >> g.V.group.by('name').by(outE.weight).by(max()) // old way >> g.V.group.by('name').by(outE.weight.max()) // new way >> >> What is the difference, there is only two by()-modulators that can be >> passed to group(): keyTraversal and valueTraversal. What happened to >> reduceTraversal? Well, valueTraversal is that. If you want to reduce on >> your values, well, add a reducing barrier step -- e.g. max, min, sum, >> count, fold, mean, etc. In the old way, we would put all your values into a >> Collection<V> and then when the step was complete, we would feed those into >> the reduceTraversal. Now -- we can dynamically reduce on the fly. This will >> greatly improve speed and memory usage as we don't have to create a big old >> Collection<V> and instead, can reduce as new traversers are fed into >> valueTraversal. >> >> So this is great and no would object. What sucks is that this is NOT >> backwards compatible. What Stephen and I came up with (in the ticket) is to >> make: >> >> >> https://github.com/apache/incubator-tinkerpop/blob/group_step_2/gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/dsl/graph/GraphTraversal.java#L637-L639 >> >> This new step groupV3d0() is a deprecated step that is what the "old way" >> was. Note the naming convention that Stephen used for Kryo is now used here >> -- V3d0 (version 3<dot>0). Thus, for users moving forward, they will have >> to do a "replace all" on their queries and rename "group()" to >> "groupV3d0()". Then slowly, over time, convert their traversal to use the >> new group() step and its respective semantics. >> >> Note that in the past we have been able to do backwards compatibility via >> having the new step (e.g. AddVertexStep) simulate the behavior of the old >> step and have respective @Deprecates in there to say that particular >> GraphTraversal methods will go away. However, in this situation, the best >> we can do is groupV3d0(). >> >> Anywho. That is that. If people have any better ideas on how to solve this >> backwards compatibility issue, I'm all (deaf) ears. >> >> Thanks, >> Marko. >> >> http://markorodriguez.com >> >>
