From baca2703f11021649c2487e8247d0191e9257ddf Mon Sep 17 00:00:00 2001
From: Tobias Beer <beertobias@gmail.com>
Date: Mon, 26 Jan 2015 13:39:04 +0100
Subject: [PATCH] added list suffix for each filter

implements #1369

when the suffix is `list`, interprets the field as a list of individual
tiddler titles and returns all titles referenced in the list field of
the source list, existing or not
---
 core/modules/filters/each.js | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/core/modules/filters/each.js b/core/modules/filters/each.js
index 591dfeae0..8126d5821 100644
--- a/core/modules/filters/each.js
+++ b/core/modules/filters/each.js
@@ -3,7 +3,8 @@ title: $:/core/modules/filters/each.js
 type: application/javascript
 module-type: filteroperator
 
-Filter operator that selects one tiddler for each unique value of the specified field
+Filter operator that selects one tiddler for each unique value of the specified field.
+With suffix "list", selects all tiddlers that are values in a specified list field.
 
 \*/
 (function(){
@@ -17,19 +18,23 @@ Export our filter function
 */
 exports.each = function(source,operator,options) {
 	var results = [],
-		values = {};
+		values = {},
+		list = "list" === operator.suffix;
 	source(function(tiddler,title) {
 		if(tiddler) {
-			var value;
-			if((operator.operand === "") || (operator.operand === "title")) {
-				value = title;
-			} else {
-				value = tiddler.getFieldString(operator.operand);
-			}
-			if(!$tw.utils.hop(values,value)) {
-				values[value] = true;
-				results.push(title);
-			}
+			var value,
+				field = operator.operand || "title";
+			$tw.utils.each(
+				list ?
+				options.wiki.getTiddlerList(title,field) :
+				[ "title" === field ? title : tiddler.getFieldString(operator.operand)],
+				function(value){
+					if(!$tw.utils.hop(values,value)) {
+						values[value] = true;
+						results.push(list ? value : title);
+					}
+				}
+			)
 		}
 	});
 	return results;