--- loncom/html/adm/LC_math_editor/src/parser.js	2014/09/24 18:14:39	1.1
+++ loncom/html/adm/LC_math_editor/src/parser.js	2015/02/24 15:20:44	1.2
@@ -18,6 +18,8 @@ through which recipients can access the
 
 */
 
+"use strict";
+
 /**
  * Equation parser
  * @constructor
@@ -34,7 +36,7 @@ function Parser(implicit_operators, unit
         this.unit_mode = false;
     else
         this.unit_mode = unit_mode;
-    if (typeof constants == "undefined")
+    if (typeof constants == "undefined" || constants == null)
         this.constants = [];
     else
         this.constants = constants;
@@ -117,7 +119,7 @@ Parser.prototype.addHiddenOperators = fu
                     in_exp = false;
                 else if (!in_exp && token.type == Token.NUMBER)
                     in_units = false;
-                else if (token.type == Token.OPERATOR && "*/^()".indexOf(token.value) == -1)
+                else if (!in_exp && token.type == Token.OPERATOR && "*/^()".indexOf(token.value) == -1)
                     in_units = false;
                 else if (token.type == Token.NAME && next_token.value == "(")
                     in_units = false;
@@ -127,18 +129,18 @@ Parser.prototype.addHiddenOperators = fu
                 (token.type == Token.NAME && next_token.type == Token.NAME) ||
                 (token.type == Token.NUMBER && next_token.type == Token.NAME) ||
                 (token.type == Token.NUMBER && next_token.type == Token.NUMBER) ||
-                (token.type == Token.NUMBER && (next_token.value == "(" || next_token.value == "[")) ||
+                (token.type == Token.NUMBER && (next_token.value == "(" || next_token.value == "[" || next_token.value == "{")) ||
                 /*(token.type == Token.NAME && next_token.value == "(") ||*/
                 /* name ( could be a function call */
-                ((token.value == ")" || token.value == "]") && next_token.type == Token.NAME) ||
-                ((token.value == ")" || token.value == "]") && next_token.type == Token.NUMBER) ||
-                ((token.value == ")" || token.value == "]") && next_token.value == "(")
+                ((token.value == ")" || token.value == "]" || token.value == "}") && next_token.type == Token.NAME) ||
+                ((token.value == ")" || token.value == "]" || token.value == "}") && next_token.type == Token.NUMBER) ||
+                ((token.value == ")" || token.value == "]" || token.value == "}") && next_token.value == "(")
            ) {
             // support for things like "(1/2) (m/s)" is complex...
             var units = (this.unit_mode && !in_units && (token.type == Token.NUMBER ||
-                (token.value == ")" || token.value == "]")) &&
+                (token.value == ")" || token.value == "]" || token.value == "}")) &&
                 (next_token.type == Token.NAME ||
-                    ((next_token.value == "(" || next_token.value == "[") && this.tokens.length > i + 2 &&
+                    ((next_token.value == "(" || next_token.value == "[" || next_token.value == "{") && this.tokens.length > i + 2 &&
                     this.tokens[i + 2].type == Token.NAME)));
             if (units) {
                 var test_token, index_test;