Add an example using nested repeat steps #115

sample-code/nested-repeat.groovy

@@ -0,0 +1,124 @@
+// Experiments with the nested repeat feature added in TinkerPop 3.4.0
+//
+// NOTE: To run you will need the Gremlin Console at the TinkerPop 3.4.0
+//       level or higher. As other vendors upgrade to TinkerPop 3.4.0
+//       you may be able to use nested repeats on those platforms also.
+
+conf = new BaseConfiguration()
+conf.setProperty("gremlin.tinkergraph.vertexIdManager","LONG")
+conf.setProperty("gremlin.tinkergraph.edgeIdManager","LONG")
+conf.setProperty("gremlin.tinkergraph.vertexPropertyIdManager","LONG")
+
+graph = TinkerGraph.open(conf)
+g = graph.traversal()
+
+g.addV('person').property('name','Amy').as('amy').
+  addV('person').property('name','Bill').as('bill').
+  addV('person').property('name','Sam').as('sam').
+  addV('person').property('name','Eric').as('eric').
+  addV('person').property('name','Frank').as('frank').
+  addV('person').property('name','Janet').as('janet').
+  addV('person').property('name','Marie').as('marie').
+  addV('person').property('name','Mark').as('mark').
+  addV('person').property('name','Pam').as('pam').
+  addV('person').property('name','Peter').as('peter').
+  addV('city').property('name','Austin').as('austin').
+  addV('city').property('name','Brighton').as('brighton').
+  addV('city').property('name','Canterbury').as('canterbury').
+  addV('city').property('name','Miami').as('miami').
+  addV('city').property('name','New York City').as('nyc').
+  addV('county').property('name','Dade').as('dade').
+  addV('county').property('name','East Sussex').as('esussex').
+  addV('county').property('name','Kent').as('kent').
+  addV('county').property('name','New York County').as('nycc').
+  addV('county').property('name','Travis').as('travis').
+  addV('state').property('name','Florida').as('florida').
+  addV('state').property('name','New York').as('ny').
+  addV('state').property('name','Texas').as('texas').
+  addV('country').property('name','USA').as('usa').
+  addV('country').property('name','England').as('england').
+  addE('knows').from('bill').to('amy').
+  addE('knows').from('bill').to('eric').
+  addE('knows').from('bill').to('frank').
+  addE('knows').from('bill').to('sam').
+  addE('knows').from('eric').to('pam').
+  addE('knows').from('eric').to('marie').
+  addE('location').from('amy').to('canterbury').
+  addE('location').from('bill').to('austin').
+  addE('location').from('eric').to('austin').
+  addE('location').from('frank').to('miami').
+  addE('location').from('janet').to('brighton').
+  addE('location').from('marie').to('canterbury').
+  addE('location').from('mark').to('miami').
+  addE('location').from('pam').to('nyc').
+  addE('location').from('peter').to('brighton').
+  addE('location').from('sue').to('brighton').
+  addE('part_of').from('austin').to('travis').
+  addE('part_of').from('brighton').to('esussex').
+  addE('part_of').from('canterbury').to('kent').
+  addE('part_of').from('miami').to('dade').
+  addE('part_of').from('nyc').to('nycc').
+  addE('part_of').from('nycc').to('ny').
+  addE('part_of').from('travis').to('texas').
+  addE('part_of').from('dade').to('florida').
+  addE('part_of').from('esussex').to('england').
+  addE('part_of').from('kent').to('england').
+  addE('part_of').from('florida').to('usa').
+  addE('part_of').from('texas').to('usa').
+  addE('part_of').from('ny').to('usa').
+  iterate()
+
+// Check the relationships we just created.
+g.V().hasLabel('person').
+      repeat(outE().inV()).
+        until(__.not(out())).
+      path().by('name').by(label)
+/*
+==>[Amy,location,Canterbury,part_of,Kent,part_of,England]
+==>[Bill,location,Austin,part_of,Travis,part_of,Texas,part_of,USA]
+==>[Bill,knows,Amy,location,Canterbury,part_of,Kent,part_of,England]
+==>[Bill,knows,Sam,location,Brighton,part_of,East Sussex,part_of,England]
+==>[Bill,knows,Eric,location,Austin,part_of,Travis,part_of,Texas,part_of,USA]
+==>[Bill,knows,Eric,knows,Pam,location,New York City,part_of,New York,part_of,USA]
+==>[Bill,knows,Frank,location,Miami,part_of,Dade,part_of,Florida,part_of,USA]
+==>[Sue,location,Brighton,part_of,East Sussex,part_of,England]
+==>[Eric,location,Austin,part_of,Travis,part_of,Texas,part_of,USA]
+==>[Eric,knows,Pam,location,New York City,part_of,New York,part_of,USA]
+==>[Frank,location,Miami,part_of,Dade,part_of,Florida,part_of,USA]
+==>[Janet,location,Brighton,part_of,East Sussex,part_of,England]
+==>[Marie,location,Canterbury,part_of,Kent,part_of,England]
+==>[Mark,location,Miami,part_of,Dade,part_of,Florida,part_of,USA]
+==>[Pam,location,New York City,part_of,New York,part_of,USA]
+==>[Peter,location,Brighton,part_of,East Sussex,part_of,England]
+*/                                                                 
+
+// Bill's friends in the USA
+g.V().has('name','Bill').
+      out('knows').as('friend').
+      repeat(out('location')).
+        until(repeat(out('part_of')).
+          emit(has('name','USA'))).
+      path().from('friend').by('name') 
+//[Frank,Miami]
+//[Eric,Austin] 
+
+//Bill's friends in England
+g.V().has('name','Bill').
+      out('knows').as('friend').
+      repeat(out('location')).
+        until(repeat(out('part_of')).
+          emit(has('name','England'))).
+      path().from('friend').by('name')  
+//[Sam,Brighton]
+//[Amy,Canterbury] 
+
+// Similar but without a nested repeat.
+// Notice the difference. We get the whole path back.
+g.V().has('name','Bill').
+      out('knows').as('friend').
+      out('location').
+         repeat(out('part_of')).
+           emit(has('name','England')).
+         path().from('friend').by('name') 
+//[Amy,Canterbury,Kent,England]         
+//[Sam,Brighton,East Sussex,England]