diff --git a/README.md b/README.md
index 04514db..83ef9a2 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,6 @@
+## Requires
+ - node
+ - npm
 
 ## Compile lemon-js
 ```bash
diff --git a/parsers/filters/parser.y b/parsers/filters/parser.y
index 7a414b1..f54449f 100644
--- a/parsers/filters/parser.y
+++ b/parsers/filters/parser.y
@@ -13,7 +13,9 @@
 %code {
     &&REPLACER{parsers/filters/test_code_environment.js}&&
 
-    var _result = {};
+    var _result = {
+        error: false
+    };
     var LemonJS = function(_input) {
         _result = Object.create(null);
         var parser = new Parser();
@@ -21,6 +23,10 @@
         var token;
         var lexemes = [];
         while (token = lexer.next()) {
+            if(_result.error) {
+                return { success: false }
+            }
+
             if (token.error === 0) {
                 console.log("PARSE", token.lexeme);
                 parser.parse(parser["TOKEN_" + token.lexeme], token);
@@ -30,6 +36,7 @@
         parser.parse();
 
         return {
+            success: true,
             tree: _result.root_node,
             lexemes: lexemes
         };
@@ -37,6 +44,7 @@
 }
 
 %syntax_error {
+    _result.error = "true";
     console.log("Syntax error");
 }