Transforms-And-Templates.md

@@ -11,9 +11,9 @@ eg: say we have an [email.smtp_forward channel](https://bip.io/docs/pods/email)
 
 Templates can also be interpolated with variables from upstream channels or metadata if they take the form 
 
-`[%(source|_client|_bip|channel id)#export_attribute%]`
+`[%(source|_client|_bip|channel id)#json_path%]`
 
-"export attribute" in the example means the name of an attribute exported by an upstream channel, keyed by either an explicit channel id, or `source` (ie: whatever the bip receives or generates). This means you can concatenate exports and text together to create a custom import.  With the previous email example, lets assume we're using an `smtp` bip and want to pass through some of the details to an email channel on its hub : 
+`json_path` in the example means the [JSON Path](http://goessner.net/articles/JsonPath/) of an attribute exported by an upstream channel, keyed by either an explicit channel id, or `source` (ie: whatever the bip receives or generates). This means you can concatenate exports and text together to create a custom import.  With the previous email example, lets assume we're using an `smtp` bip and want to pass through some of the details to an email channel on its hub : 
 
 ```
 {
@@ -21,6 +21,35 @@ Templates can also be interpolated with variables from upstream channels or meta
   "body_text" : "I got an email from [%_client#repr%] : [%source#body_text%]"
 }
 ```
+
+## Object and Array Passthrough
+
+Transform templates which only include a single JSONPath will be evaluated in-place, meaning that if the path evaluates to an object or array, then it will be replaced with that structured data.
+
+For example, say we have a channel with a `json_document` import which expects a structured object and you need to map an export object from a complex payload like so (the 2nd object element of an array) : 
+
+```
+{
+  "374d9a1d-cc84-456d-9dad-e1e3065e8c4d" : {
+    "payload" : [
+      "Payload Title",
+      {
+        "name" : "This is the document name",
+        "value" : "And it has a value"
+      }
+    ]
+  }
+}
+```
+
+It can mapped as : 
+
+```
+{
+  "json_document" : "[%374d9a1d-cc84-456d-9dad-e1e3065e8c4d#payload[1].body%]"
+}
+```
+
 ## Bip metadata exports (_bip|_client)
 
 Additional metadata exports are available depending on the type of Bip that is evaluating. These exports are set in `_bip` and `_client` exports which can be discovered by calling the [`/rpc/describe/bip`](https://github.com/bipio-server/bipio/wiki/Describing-Models) RPC.