From d313bc78a478f9457ce8b496ede0b231e6b4d0f1 Mon Sep 17 00:00:00 2001
From: Benny Wu <benzwu@gmail.com>
Date: Tue, 11 Aug 2015 09:33:13 +0700
Subject: [PATCH] Documentation update on Template Where Function for nil

---
 docs/content/templates/functions.md | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/docs/content/templates/functions.md b/docs/content/templates/functions.md
index cbb288efa..5fe31aaa9 100644
--- a/docs/content/templates/functions.md
+++ b/docs/content/templates/functions.md
@@ -265,6 +265,22 @@ Following operators are now available
        {{ .Content }}
     {{ end }}
 
+### Unset field
+Filter only work for set fields. To check whether a field is set or exist, use operand `nil`.
+
+This can be useful to filter a small amount of pages from a large pool. Instead of set field on all pages, you can set field on required pages only.
+
+Only following operators are available for `nil`
+
+- `=`, `==`, `eq`: True if the given field is not set.
+- `!=`, `<>`, `ne`: True if the given field is set.
+
+e.g.
+
+    {{ range where .Data.Pages ".Params.specialpost" "!=" nil }}
+       {{ .Content }}
+    {{ end }}
+
 
 ## Math