1 files changed, 11 insertions, 6 deletions
diff --git a/lib/template.js b/lib/template.js
index 32c46de..69a1bd5 100644
--- a/lib/template.js
+++ b/lib/template.js
@@ -45,6 +45,7 @@ var BookLoader = nunjucks.Loader.extend({
 
 var TemplateEngine = function(book) {
 	this.book = book;
+    this.log = this.book.log;
 
 	// Nunjucks env
 	this.env = new nunjucks.Environment(
@@ -66,12 +67,16 @@ var TemplateEngine = function(book) {
 	);
 };
 
-// Add filters
-TemplateEngine.prototype.addFilters = function(filters) {
-    _.each(filters, function(func, key) {
-        this.book.log.debug.ln("add filter '"+key+"'");
-        this.env.addFilter(key, func);
-    }, this);
+
+// Add filter
+TemplateEngine.prototype.addFilter = function(key, filter) {
+    if (this.env.getFilter(filterName)) {
+        this.log.warn.ln("conflict in filters, '"+filterName+"' is already set");
+        return false;
+    }
+    this.log.debug.ln("add filter '"+key+"'");
+    this.env.addFilter(key, func, true);
+    return true;
 };
 
 // Render a string from the book