From 65654ddbf95be684819285097f4c0ffb83229e66 Mon Sep 17 00:00:00 2001
From: Slim Bouguerra <bslim@yahoo-inc.com>
Date: Mon, 27 Jul 2015 16:23:14 -0500
Subject: [PATCH] adding documentation about extraction filter

---
 docs/content/querying/filters.md | 33 ++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/docs/content/querying/filters.md b/docs/content/querying/filters.md
index 0fe931dbb96..2cc780bcd89 100644
--- a/docs/content/querying/filters.md
+++ b/docs/content/querying/filters.md
@@ -80,3 +80,36 @@ The following matches any dimension values for the dimension `name` between `'ba
   "function" : "function(x) { return(x >= 'bar' && x <= 'foo') }"
 }
 ```
+
+### Extraction filter
+
+Extraction filter matches a dimension using some specific [Extraction function](./dimensionspecs.html#extraction-functions).
+The filter matches the values for which the extraction function has transformation entry `input_key=output_value` where
+ `output_value` is equal to the filter `value` and `input_key` is present as dimension.
+
+**Example**
+The following matches dimension values in `[product_1, product_3, product_5]` for the column `product`
+
+```json
+{
+    "filter": {
+        "type": "extraction",
+        "dimension": "product",
+        "value": "bar_1",
+        "extractionFn": {
+            "type": "lookup",
+            "lookup": {
+                "type": "map",
+                "map": {
+                    "product_1": "bar_1",
+                    "product_5": "bar_1",
+                    "product_3": "bar_1"
+                }
+            },
+            "replaceMissingValueWith": "",
+            "retainMissingValue": false,
+            "injective": false
+        }
+    }
+}
+```