Add more documentation about element composition's relationship to incremental dom
@@ -271,3 +271,41 @@ except `class`.
<{example()} data-foo="3"></>
{/template}
```
+
+#### Incremental DOM {#incrementaldom}
+
+Element composition shares many of the properties that `calls` do.
+
+Keys can be represented using the `key` command.
+
+```soy
+{template a}
+ <{foo()} {key 0}></>
+{/template}
+```
+
+`{skip}` does not work on element composition calls.
+
+```soy {.bad}
+{template a}
+ <{foo()} {skip}></> // not allowed
+{/template}
+```
+
+In a Soy element, you can use element composition to call a Soy template. You
+cannot use element composition to call another Soy element.
+
+```soy
+
+{template base kind="html<?>"}
+ <div></div>
+{/template}
+
+{element a kind="html<?>"}
+ <{base()} /> // This is allowed
+{/element}
+
+{element b}
+ <{a()} /> // This is not
+{/element}
+```
