--- a/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/TruffleLanguage.java	Wed May 27 00:36:16 2015 +0200
+++ b/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/TruffleLanguage.java	Wed May 27 13:32:18 2015 +0200
@@ -133,13 +133,19 @@
     public static final class Env {
         private final TruffleVM vm;
         private final TruffleLanguage lang;
+        private final Reader in;
+        private final Writer err;
+        private final Writer out;
 
-        Env(TruffleVM vm, Constructor<?> langConstructor) {
+        Env(TruffleVM vm, Constructor<?> langConstructor, Writer out, Writer err, Reader in) {
             this.vm = vm;
+            this.in = in;
+            this.err = err;
+            this.out = out;
             try {
                 this.lang = (TruffleLanguage) langConstructor.newInstance(this);
             } catch (Exception ex) {
-                throw new IllegalStateException("Cannot construct language " + langConstructor.getClass().getName(), ex);
+                throw new IllegalStateException("Cannot construct language " + langConstructor.getDeclaringClass().getName(), ex);
             }
         }
 
@@ -155,15 +161,41 @@
         public Object importSymbol(String globalName) {
             return API.importSymbol(vm, lang, globalName);
         }
+
+        /**
+         * Input associated with this {@link TruffleVM}.
+         *
+         * @return reader, never <code>null</code>
+         */
+        public Reader stdIn() {
+            return in;
+        }
+
+        /**
+         * Standard output writer for this {@link TruffleVM}.
+         *
+         * @return writer, never <code>null</code>
+         */
+        public Writer stdOut() {
+            return out;
+        }
+
+        /**
+         * Standard error writer for this {@link TruffleVM}.
+         *
+         * @return writer, never <code>null</code>
+         */
+        public Writer stdErr() {
+            return err;
+        }
     }
 
     private static final AccessAPI API = new AccessAPI();
 
     private static final class AccessAPI extends Accessor {
-
         @Override
-        protected TruffleLanguage attachEnv(TruffleVM vm, Constructor<?> langClazz) {
-            Env env = new Env(vm, langClazz);
+        protected TruffleLanguage attachEnv(TruffleVM vm, Constructor<?> langClazz, Writer stdOut, Writer stdErr, Reader stdIn) {
+            Env env = new Env(vm, langClazz, stdOut, stdErr, stdIn);
             return env.lang;
         }