Method to collect errors from AST

--HG--
branch : dev

src/Orchard.Web/Modules/Orchard.Widgets/SimpleScripting/Ast/AbstractSyntaxTree.cs

@@ -1,5 +1,33 @@
-namespace Orchard.Widgets.SimpleScripting.Ast {
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Orchard.Widgets.SimpleScripting.Ast {
     public class AbstractSyntaxTree {
         public AstNode Root { get; set; }
+
+        public IEnumerable<ErrorAstNode> GetErrors() {
+            return new ErrorNodeCollector().Collect(Root);
+        }
+    }
+
+    public class ErrorNodeCollector : AstVisitor {
+        private readonly List<ErrorAstNode> _errors = new List<ErrorAstNode>();
+
+        public IEnumerable<ErrorAstNode> Collect(AstNode root) {
+            this.Visit(root);
+            return _errors;
+        }
+
+        public override object Visit(AstNode node) {
+            var result = node.Accept(this);
+            VisitChildren(node);
+            return result;
+        }
+
+        public override object VisitError(ErrorAstNode node) {
+            _errors.Add(node);
+            return null;
+        }
     }
 }