Hello,
I am aware that all of this will be improved in TinkerPop 4.
Suggestion to introduce type predicates in TinkerPop 3:
`...is(P.vertexType())...` or `...is(P.type(Type.vertex))...`
with imports:
`...is(vertexType())...` or `...is(P.type(vertex))...`
TinkerPop 3 type system depends on the implementation, but there are some
common types like Vertex, Edge, Map, List, String...
Depending on the type, different steps are required to perform similar
operations. For example, access by index:
* `values(i)` to get property from vertex or edge
* `select(i)` to get value from map
In complex traversals, it might be complicated to track type. This might be
improved by introducing type predicates:
`...select('unknown').choose(mapType(), select('p'), values('p'))`
Another use case - filter path elements. For example, getting all vertices from
path with mixed order of elements
`g.V().limit(1).out().out().inE().outV().path().as('myPath)` is not trivial
task. This could be achieved by:
`...select('myPath').unfold().is(vertexType())`
Some steps depend on type:
`g.V().values('prop1').max()` will fail with `java.lang.Integer cannot be cast
to java.lang.String` if `prop1` has different types. This could be addressed:
`g.V().values('prop1').is(numericType()).max()`
This requirement is actual for Cypher for Gremlin. I am very interested to know
if this requirement is language translation specific, or have other use cases.
Please share your opinion on this.
Regards,
Dmitry
