diff -r 6c1fa412c72d -r dd4dabfead82 rt/vm/src/main/java/org/apidesign/vm4brwsr/Bck2Brwsr.java
--- a/rt/vm/src/main/java/org/apidesign/vm4brwsr/Bck2Brwsr.java	Fri Mar 13 11:41:04 2015 +0100
+++ b/rt/vm/src/main/java/org/apidesign/vm4brwsr/Bck2Brwsr.java	Fri Sep 11 14:51:09 2015 +0200
@@ -422,10 +422,10 @@
      */
     public static final class Flow {
         private final MethodData m;
-        private byte[] ops;
-        Flow(MethodData m) {
+        private final Appendable emit;
+        Flow(MethodData m, Appendable emit) {
             this.m = m;
-            ops = new byte[m.getCode().length];
+            this.emit = emit;
         }
         
         /** Access to bytecode of the method to analyse.
@@ -442,47 +442,12 @@
         public String getMethodName() {
             return m.getName();
         }
-        
-        public void beginLoopAt(int bci) {
-            ops[bci] |= 0x10;
-        }
-        
-        public void beginIfAt(int bci) {
-            ops[bci] |= 0x20;
-        }
 
-
-        public void breakAt(int bci) {
-            ops[bci] |= 0x40;
-        }
-
-        public void beginElseAt(int bci) {
-            ops[bci] |= 0x80;
-        }
-
-        public void endAt(int bci) {
-            int cnt = (ops[bci] & 0x0f) + 1;
-            int rest = ops[bci] & 0xf0;
-            ops[bci] = (byte)(rest | cnt);
-        }
-        
-        boolean isFlow(int at) {
-            return ops[at] != 0;
-        }
-        boolean isLoop(int at) {
-            return (ops[at] & 0x10) != 0;
-        }
-        boolean isIf(int at) {
-            return (ops[at] & 0x20) != 0;
-        }
-        boolean isBreak(int at) {
-            return (ops[at] & 0x40) != 0;
-        }
-        boolean isElse(int at) {
-            return (ops[at] & 0x80) != 0;
-        }
-        int isEnd(int at) {
-            return (ops[at] & 0x0f);
+        /** Emits JavaScript to the final JavaScript output.
+         * @param seq text to emit
+         */
+        public void emit(CharSequence seq) throws IOException {
+            this.emit.append(seq);
         }
         
         /** Provider of advanced analysis of the code flow inside of
@@ -500,7 +465,7 @@
              * @return <code>true</code> if the analysis was successful,
              *   <code>false</code> otherwise
              */
-            public boolean analyze(Flow request);
+            public boolean analyze(Flow request) throws IOException;
         }
     }