diff --git a/core/modules/parsers/parseutils.js b/core/modules/parsers/parseutils.js
index 53dfc48c0..18bcdd516 100644
--- a/core/modules/parsers/parseutils.js
+++ b/core/modules/parsers/parseutils.js
@@ -528,67 +528,79 @@ exports.parseAttribute = function(source,pos) {
 		pos = token.end;
 		// Skip whitespace
 		pos = $tw.utils.skipWhiteSpace(source,pos);
-		// Look for a string literal
-		var stringLiteral = $tw.utils.parseStringLiteral(source,pos);
-		if(stringLiteral) {
-			pos = stringLiteral.end;
-			node.type = "string";
-			node.value = stringLiteral.value;
-		} else {
+		do {
+			// Look for a string literal
+			var stringLiteral = $tw.utils.parseStringLiteral(source,pos);
+			if(stringLiteral) {
+				pos = stringLiteral.end;
+				node.type = "string";
+				node.value = stringLiteral.value;
+				break;
+			}
+
 			// Look for a filtered value
 			var filteredValue = $tw.utils.parseTokenRegExp(source,pos,reFilteredValue);
 			if(filteredValue) {
 				pos = filteredValue.end;
 				node.type = "filtered";
 				node.filter = filteredValue.match[1];
-			} else {
-				// Look for an indirect value
-				var indirectValue = $tw.utils.parseTokenRegExp(source,pos,reIndirectValue);
-				if(indirectValue) {
-					pos = indirectValue.end;
-					node.type = "indirect";
-					node.textReference = indirectValue.match[1];
-				} else {
-					// Look for a macro invocation value
-					var macroInvocation = $tw.utils.parseMacroInvocationAsTransclusion(source,pos);
-					if(macroInvocation) {
-						pos = macroInvocation.end;
-						node.type = "macro";
-						node.value = macroInvocation;
-					} else {
-						// Look for an MVV reference value
-						var mvvReference = $tw.utils.parseMVVReferenceAsTransclusion(source,pos);
-						if(mvvReference) {
-							pos = mvvReference.end;
-							node.type = "macro";
-							node.value = mvvReference;
-							node.isMVV = true;
-						} else {
-							var substitutedValue = $tw.utils.parseTokenRegExp(source,pos,reSubstitutedValue);
-							if(substitutedValue) {
-								pos = substitutedValue.end;
-								node.type = "substituted";
-								node.rawValue = substitutedValue.match[1] || substitutedValue.match[2];
-							} else {
-								// Look for a unquoted value
-								var unquotedValue = $tw.utils.parseTokenRegExp(source,pos,reUnquotedAttribute);
-								if(unquotedValue) {
-									pos = unquotedValue.end;
-									node.type = "string";
-									node.value = unquotedValue.match[1];
-								} else if(source.charAt(pos) === "<" && source.charAt(pos + 1) === "<" && source.indexOf(">>",pos) !== -1) {
-									// Value looks like a macro invocation (starts with << with a closing >> ahead) but does not parse as one. Return null so the enclosing tag fails to parse rather than silently binding the attribute to "true" and treating the remainder as further attributes (restores v5.3.8 behaviour)
-									return null;
-								} else {
-									node.type = "string";
-									node.value = "true";
-								}
-							}
-						}
-					}
-				}
+				break;
 			}
-		}
+
+			// Look for an indirect value
+			var indirectValue = $tw.utils.parseTokenRegExp(source,pos,reIndirectValue);
+			if(indirectValue) {
+				pos = indirectValue.end;
+				node.type = "indirect";
+				node.textReference = indirectValue.match[1];
+				break;
+			}
+
+			// Look for a macro invocation value
+			var macroInvocation = $tw.utils.parseMacroInvocationAsTransclusion(source,pos);
+			if(macroInvocation) {
+				pos = macroInvocation.end;
+				node.type = "macro";
+				node.value = macroInvocation;
+				break;
+			}
+
+			// Look for an MVV reference value
+			var mvvReference = $tw.utils.parseMVVReferenceAsTransclusion(source,pos);
+			if(mvvReference) {
+				pos = mvvReference.end;
+				node.type = "macro";
+				node.value = mvvReference;
+				node.isMVV = true;
+				break;
+			}
+
+			// Look for a substituted value
+			var substitutedValue = $tw.utils.parseTokenRegExp(source,pos,reSubstitutedValue);
+			if(substitutedValue) {
+				pos = substitutedValue.end;
+				node.type = "substituted";
+				node.rawValue = substitutedValue.match[1] || substitutedValue.match[2];
+				break;
+			}
+
+			// Look for a unquoted value
+			var unquotedValue = $tw.utils.parseTokenRegExp(source,pos,reUnquotedAttribute);
+			if(unquotedValue) {
+				pos = unquotedValue.end;
+				node.type = "string";
+				node.value = unquotedValue.match[1];
+				break;
+			}
+
+			if(source.charAt(pos) === "<" && source.charAt(pos + 1) === "<" && source.indexOf(">>",pos) !== -1) {
+				// Value looks like a macro invocation (starts with << with a closing >> ahead) but does not parse as one. Return null so the enclosing tag fails to parse rather than silently binding the attribute to "true" and treating the remainder as further attributes (restores v5.3.8 behaviour)
+				return null;
+			}
+
+			node.type = "string";
+			node.value = "true";
+		} while(false);
 	} else {
 		// If there is no equals sign or colon, then this is an attribute with no value, defaulting to "true"
 		node.type = "string";