diff --git a/src/parser.js b/src/parser.js
index 9b2a7c5..0caff5a 100644
--- a/src/parser.js
+++ b/src/parser.js
@@ -273,9 +273,7 @@ PEG.parser = (function(){
         result0 = parse_identifier();
         if (result0 !== null) {
           result1 = parse_string();
-          if (result1 === null) {
-            result1 = "";
-          }
+          result1 = result1 !== null ? result1 : "";
           if (result1 !== null) {
             result2 = parse_equals();
             if (result2 !== null) {
@@ -799,9 +797,7 @@ PEG.parser = (function(){
           reportFailures++;
           pos3 = pos;
           result1 = parse_string();
-          if (result1 === null) {
-            result1 = "";
-          }
+          result1 = result1 !== null ? result1 : "";
           if (result1 !== null) {
             result2 = parse_equals();
             if (result2 !== null) {
diff --git a/src/parser.pegjs b/src/parser.pegjs
index a258c7c..fe199d2 100644
--- a/src/parser.pegjs
+++ b/src/parser.pegjs
@@ -20,7 +20,7 @@ initializer
     }
 
 rule
-  = name:identifier displayName:(string / "") equals expression:expression semicolon? {
+  = name:identifier displayName:string? equals expression:expression semicolon? {
       return {
         type:        "rule",
         name:        name,
@@ -130,7 +130,7 @@ suffixed
   / primary
 
 primary
-  = name:identifier !(( string / "") equals) {
+  = name:identifier !(string? equals) {
       return {
         type: "rule_ref",
         name: name