added .getActionAttrAliased(..)

Signed-off-by: Alex A. Naanou <alex.nanou@gmail.com>

README.md

@@ -517,6 +517,9 @@ Attribute access:
 <action-set>.getActionAttr('action', 'attr')
     -> <value>
 
+<action-set>.getActionAttrAliased('action', 'attr')
+    -> <value>
+
 <action-set>.getRootActionAttr('action', 'attr')
     -> <value>
 ```

actions.js

@@ -1048,6 +1048,29 @@ module.MetaActions = {
 		if(cur[action] != null && action != '__actioncall__'){
 			return this.getActionAttr('__actioncall__', attr) } },
 
+	// Get action attribute with alias support...
+	//
+	// An aliased attribute is one containing a string name of another 
+	// action.
+	//
+	// To avoid things changing when actions are added/removed this does 
+	// not support string attrubute values.
+	getActionAttrAliased: function(action, attr){
+		var value = action
+		var seen = new Set()
+		do {
+			// recursive alias...
+			if(seen.has(value)){
+				throw new Error(
+					'getActionAttrAliased: recursive alias for "'+ attr +'": '
+					// XXX should we split seen at value???
+					+ [...seen, value].join(' -> ')) }
+			seen.add(value)
+			// next value...
+			value = this.getActionAttr(value, attr)
+		} while(typeof(value) == 'string')
+		return value },
+
 	// Get root action attribute value...
 	//
 	// This is similar to .getActionAttr(..) but will only chenck the 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ig-actions",
-  "version": "3.24.30",
+  "version": "3.25.0",
   "description": "",
   "main": "actions.js",
   "scripts": {