Add more examples to local collections discussion. Start discussion o…

…f TInkerPop 3.4

book/Gremlin-Graph-Guide.adoc

@@ -2,9 +2,9 @@ PRACTICAL GREMLIN: An Apache TinkerPop Tutorial
 ===============================================
 Kelvin R. Lawrence <[email protected]>
 //v281 (TP 3.3.5), January 28th 2019
-v282-preview, March 2nd 2019
+v282-preview, March 31st 2019
 // vim: set tw=85 cc=+1 wrap spell redrawtime=20000:
-//Sat Mar 02, 2019 10:04:01
+// Sun Mar 31, 2019 10:36:57
 //:Author:    Kelvin R. Lawrence
 //:Email:     [email protected]
 :Numbered:
@@ -25,8 +25,8 @@ v282-preview, March 2nd 2019
 :doctype: book
 :icons: font
 //:pdf-page-size: Letter
-:draftdate: March 2nd 2019
-:tpvercheck: 3.3.5
+:draftdate: March 31st 2019
+:tpvercheck: 3.4.0
 
 // NOTE1: I updated the paraiso-dark style so that source code with a style of text
 //        has a white foreground color. The default was unreadable,
@@ -163,8 +163,9 @@ examples presented will work unmodified with the `air-routes.graphml` file loade
 the Gremlin console running with a TinkerGraph. How to set that environment up is
 covered in the <<gremlininstall>> section below.
 
-NOTE: The examples in this book have now been updated and tested using Apache
-TinkerPop release {tpvercheck}.
+NOTE: The examples in this book have been tested using Apache TinkerPop release
+{tpvercheck}. However, work remains to be done to add coverage of new features in
+that release to the book.
 
 TinkerGraph is an 'in-memory' graph, meaning nothing gets saved to disk
 automatically. It is shipped as part of the Apache TinkerPop 3 download.  The
@@ -294,6 +295,20 @@ Change history::
   on.
 - https://github.com/krlawrence/graph/blob/master/ChangeHistory.md
 
+[[tp34intro]]
+A word about TinkerPop 3.4
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A major update to Apache TinkerPop, release 3.4.0 was released in January 2019. The
+examples in this book have been tested with TinkerPop 3.4.0 but the text does not yet
+include coverage of all the new features, changes and deprecations  introduced with
+that release. Be aware also that given the scope of the 3.4.0 release it may take a while
+before all of the vendor and open source graph implementations that support Apache
+TinkerPop have caught up with all of these new features. I plan to add coverage of
+these features over the coming weeks to the book. I also plan to add additional
+sample code to the `sample-code` folder. By way of a start I have recently added a
+sample called `nested-repeat.groovy` that demonstrates the use of the new nested
+repeat step capability from the Gremlin console.
 
 [[whygraph]]
 So what is a graph database and why should I care?
@@ -10267,6 +10282,37 @@ g.V().has('airport','country','IE').
 [KIR,ORK]
 ----
 
+You can combine the 'limit' and 'tail' steps with 'local' scope to extract the
+beginning or ending entries from a list of values as shown below.  The following
+query creates a list containing the IATA codes for all airports in Texas.
+
+[source,groovy]
+----
+g.V().has('region','US-TX').values('code').fold()
+
+[AUS,DFW,IAH,SAT,HOU,ELP,DAL,LBB,HRL,MAF,CRP,ABI,ACT,CLL,BPT,AMA,BRO,GGG,GRK,LRD,MFE,SJT,SPS,TYR,VCT,AFW]
+----
+
+Using 'local' scope with a 'limit' step we can extract just the first two entries
+from the list.
+
+[source,groovy]
+----
+g.V().has('region','US-TX').values('code').fold().limit(local,2)
+
+[AUS,DFW]
+----
+
+Likewise, using 'local' scope with a 'tail' step we can extract just the last two
+entries from the list.
+
+[source,groovy]
+----
+g.V().has('region','US-TX').values('code').fold().tail(local,2)
+
+[VCT,AFW]
+----
+
 Lastly, let's take a look at how 'local' scope can be used with a 'dedup' step. The
 query below finds airports in the US and produces a sorted list of the unique region
 codes by only allowing one airport from each region to proceed to the next steps of