Github user twilmes commented on a diff in the pull request:
https://github.com/apache/tinkerpop/pull/893#discussion_r205648775
--- Diff: docs/src/reference/the-traversal.asciidoc ---
@@ -1049,6 +1050,179 @@ inject(1,2).map {it.get() + 1}.map
{g.V(it.get()).next()}.values('name')
link:++http://tinkerpop.apache.org/javadocs/x.y.z/core/org/apache/tinkerpop/gremlin/process/traversal/dsl/graph/GraphTraversal.html#inject-E...-++[`inject(Object)`]
+[[_gremlin_i_o]]
+[[io-step]]
+=== IO Step
+
+image:gremlin-io.png[width=250,float=left] The task of importing and
exporting the data of `Graph` instances is the
+job of the `io()`-step. By default, TinkerPop supports three formats for
importing and exporting graph data in
+<<graphml,GraphML>>, <<graphson,GraphSON>>, and <<gryo,Gryo>>.
+
+NOTE: Additional documentation for TinkerPop IO formats can be found in
the link:http://tinkerpop.apache.org/docs/x.y.z/dev/io/[IO Reference].
+
+By itself the `io()` step merely configures the kind of importing and
exporting that is going
+to occur and it is the follow-on call to the `read()` or `write()` step
that determines which of those actions will
+execute. Therefore, a typical usage of the `io()` step would look like
this:
+
+[source,java]
+----
+g.io(someInputFile).read().iterate()
+g.io(someOutputFile).write().iterate()
+----
+
+IMPORTANT: The commands above are still traversals and therefore require
iteration to be executed, hence the use of
+`iterate()` as a termination step.
+
+By default, the `io()` step will try to detect the right file format using
the file name extension. To gain greater
+control of the format use the `with()` step modulator to provide further
information to `io()`. For example:
+
+[source,java]
+----
+g.io(someInputFile).
+ with(IO.reader, IO.graphson).
+ read().iterate()
+g.io(someOutputFile).
+ with(IO.writer,IO.graphml).
+ write().iterate()
+----
+
+The `IO` class is a helper for the `io()` step that provides expressions
that can be used to help configure it
+and in this case it allows direct specification of the "reader" or
"writer" to use. The "reader" actually refers to
+a `GraphReader` implementation and the `writer" refers to a `GraphWriter`
implementation. The implementations of
--- End diff --
Small typo here, a quote at the end of `writer"` instead of a tick.
---
