From e5f4f7b85fbb91a293a7d89d7b85adfbaeeb51f4 Mon Sep 17 00:00:00 2001
From: Thalia Archibald <thalia@archibald.dev>
Date: Fri, 21 Jun 2024 06:13:09 -0700
Subject: Format whitespace (#86)

* Trim trailing whitespace

* Ensure final new lines

* Convert line endings from CRLF to LF

* Replace tabs with spaces
---
 .../java/com/seaofnodes/simple/GraphEvaluator.java | 362 ++++----
 .../com/seaofnodes/simple/GraphVisualizer.java     |  12 +-
 .../main/java/com/seaofnodes/simple/Parser.java    |  22 +-
 .../src/main/java/com/seaofnodes/simple/Utils.java |   2 +-
 .../java/com/seaofnodes/simple/node/AddNode.java   |  26 +-
 .../java/com/seaofnodes/simple/node/BoolNode.java  |   4 +-
 .../com/seaofnodes/simple/node/ConstantNode.java   |   8 +-
 .../java/com/seaofnodes/simple/node/DivNode.java   |   4 +-
 .../java/com/seaofnodes/simple/node/IfNode.java    |   2 +-
 .../java/com/seaofnodes/simple/node/LoopNode.java  |   2 +-
 .../java/com/seaofnodes/simple/node/MinusNode.java |   6 +-
 .../java/com/seaofnodes/simple/node/MulNode.java   |   6 +-
 .../java/com/seaofnodes/simple/node/MultiNode.java |   2 +-
 .../main/java/com/seaofnodes/simple/node/Node.java |  42 +-
 .../java/com/seaofnodes/simple/node/NotNode.java   |   6 +-
 .../java/com/seaofnodes/simple/node/PhiNode.java   |   6 +-
 .../java/com/seaofnodes/simple/node/ProjNode.java  |   2 +-
 .../com/seaofnodes/simple/node/RegionNode.java     |   2 +-
 .../com/seaofnodes/simple/node/ReturnNode.java     |   4 +-
 .../java/com/seaofnodes/simple/node/ScopeNode.java |   8 +-
 .../java/com/seaofnodes/simple/node/StartNode.java |   2 +-
 .../java/com/seaofnodes/simple/node/StopNode.java  |   2 +-
 .../java/com/seaofnodes/simple/node/SubNode.java   |   2 +-
 .../main/java/com/seaofnodes/simple/type/Type.java |   4 +-
 .../com/seaofnodes/simple/type/TypeInteger.java    |   2 +-
 .../java/com/seaofnodes/simple/type/TypeTuple.java |   2 +-
 .../java/com/seaofnodes/simple/Chapter08Test.java  |  72 +-
 .../java/com/seaofnodes/simple/Fuzzer08Test.java   |  52 +-
 .../java/com/seaofnodes/simple/fuzzer/Fuzzer.java  | 256 +++---
 .../com/seaofnodes/simple/fuzzer/FuzzerUtils.java  | 116 +--
 .../java/com/seaofnodes/simple/fuzzer/Reducer.java | 288 +++----
 .../seaofnodes/simple/fuzzer/ScriptGenerator.java  | 924 ++++++++++-----------
 32 files changed, 1125 insertions(+), 1125 deletions(-)

(limited to 'chapter08/src')

diff --git a/chapter08/src/main/java/com/seaofnodes/simple/GraphEvaluator.java b/chapter08/src/main/java/com/seaofnodes/simple/GraphEvaluator.java
index b89189f5..f5694a78 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/GraphEvaluator.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/GraphEvaluator.java
@@ -1,181 +1,181 @@
-package com.seaofnodes.simple;
-
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-
-import java.util.Arrays;
-import java.util.BitSet;
-import java.util.HashMap;
-
-public class GraphEvaluator {
-
-    public enum ResultType { VALUE, FALLTHROUGH, TIMEOUT }
-
-    public record Result(ResultType type, long value) {}
-
-    /**
-     * Find the start node from some node in the graph or null if there is no start node
-     */
-    private static StartNode findStart(BitSet visit, Node node) {
-        if (node == null) return null;
-        if (node instanceof StartNode start) return start;
-        if( visit.get(node._nid) ) return null;
-        visit.set(node._nid);
-        for( Node def : node._inputs ) {
-            var res = findStart(visit,def);
-            if( res != null ) return res;
-        }
-        for( Node use : node._outputs ) {
-            var res = findStart(visit,use);
-            if( res != null ) return res;
-        }
-        return null;
-    }
-
-    /**
-     * Find the control output from a control node
-     */
-    private static Node findControl(Node control) {
-        for( Node use : control._outputs ) {
-            if (use.isCFG()) return use;
-        }
-        return null;
-    }
-
-    /**
-     * Find the projection for a node
-     */
-    private static ProjNode findProjection(Node node, int idx) {
-        for( Node use : node._outputs ) {
-            if (use instanceof ProjNode proj && proj._idx == idx) return proj;
-        }
-        return null;
-    }
-
-    /**
-     * Cache values for phi and parameter projection nodes.
-     */
-    private final HashMap<Node, Long> cacheValues = new HashMap<>();
-    /**
-     * Cache for loop phis as they can depend on itself or other loop phis
-     */
-    private long[] loopPhiCache = new long[16];
-
-    private GraphEvaluator() {
-    }
-
-    private long div(DivNode div) {
-        long in2 = getValue(div.in(2));
-        return in2 == 0 ? 0 : getValue(div.in(1)) / in2;
-    }
-
-    /**
-     * Calculate the value of a node
-     */
-    private long getValue(Node node) {
-        var cache = cacheValues.get(node);
-        if (cache != null) return cache;
-        return switch (node) {
-            case ConstantNode cons  -> ((TypeInteger)cons.compute()).value();
-            case AddNode      add   -> getValue(add.in(1)) + getValue(add.in(2));
-            case BoolNode.EQ  eq    -> getValue(eq.in(1)) == getValue(eq.in(2)) ? 1 : 0;
-            case BoolNode.LE  le    -> getValue(le.in(1)) <= getValue(le.in(2)) ? 1 : 0;
-            case BoolNode.LT  lt    -> getValue(lt.in(1)) <  getValue(lt.in(2)) ? 1 : 0;
-            case DivNode      div   -> div(div);
-            case MinusNode    minus -> -getValue(minus.in(1));
-            case MulNode      mul   -> getValue(mul.in(1)) * getValue(mul.in(2));
-            case NotNode      not   -> getValue(not.in(1)) == 0 ? 1 : 0;
-            case SubNode      sub   -> getValue(sub.in(1)) - getValue(sub.in(2));
-            default                 -> throw Utils.TODO("Unexpected node " + node);
-        };
-    }
-
-    /**
-     * Special case of latchPhis when phis can depend on phis of the same region.
-     */
-    private void latchLoopPhis(RegionNode region, Node prev) {
-        int idx = Utils.find(region._inputs, prev);
-        assert idx > 0;
-        int i = 0;
-        for( Node use : region._outputs ) {
-            if (use instanceof PhiNode phi) {
-                var value = getValue(phi.in(idx));
-                if (i == loopPhiCache.length) loopPhiCache = Arrays.copyOf(loopPhiCache, loopPhiCache.length*2);
-                loopPhiCache[i++] = value;
-            }
-        }
-        i = 0;
-        for( Node use : region._outputs ) {
-            if (use instanceof PhiNode phi) cacheValues.put(phi, loopPhiCache[i++]);
-        }
-    }
-
-    /**
-     * Calculate the values of phis of the region and caches the values. The phis are not allowed to depend on other phis of the region.
-     */
-    private void latchPhis(RegionNode region, Node prev) {
-        int idx = Utils.find(region._inputs, prev);
-        assert idx > 0;
-        for( Node use : region._outputs ) {
-            if (use instanceof PhiNode phi) {
-                var value = getValue(phi.in(idx));
-                cacheValues.put(phi, value);
-            }
-        }
-    }
-
-    /**
-     * Run the graph until either a return is found or the number of loop iterations are done.
-     */
-    private Result evaluate(StartNode start, long parameter, int loops) {
-        var parameter1 = findProjection(start, 1);
-        if (parameter1 != null) cacheValues.put(parameter1, parameter);
-        Node control = findProjection(start, 0);
-        Node prev = start;
-        while (control != null) {
-            Node next;
-            switch (control) {
-                case RegionNode region -> {
-                    if (region instanceof LoopNode && region.in(1) != prev) {
-                        if (loops--<=0) return new Result(ResultType.TIMEOUT, 0);
-                        latchLoopPhis(region, prev);
-                    } else {
-                        latchPhis(region, prev);
-                    }
-                    next = findControl(region);
-                }
-                case IfNode cond -> next = findProjection(cond, getValue(cond.in(1)) != 0 ? 0 : 1);
-                case ReturnNode ret -> {
-                    return new Result(ResultType.VALUE, getValue(ret.in(1)));
-                }
-                case ProjNode ignored -> next = findControl(control);
-                default -> throw Utils.TODO("Unexpected control node " + control);
-            }
-            prev = control;
-            control = next;
-        }
-        return new Result(ResultType.FALLTHROUGH, 0);
-    }
-
-    public static long evaluate(Node graph) {
-        return evaluate(graph, 0);
-    }
-
-    public static long evaluate(Node graph, long parameter) {
-        return evaluate(graph, parameter, 1000);
-    }
-
-    public static long evaluate(Node graph, long parameter, int loops) {
-        var res = evaluateWithResult(graph, parameter, loops);
-        if (res.type==ResultType.TIMEOUT) throw new RuntimeException("Timeout");
-        return res.value;
-    }
-
-    public static Result evaluateWithResult(Node graph, long parameter, int loops) {
-        var start = findStart(new BitSet(), graph);
-        if (start == null) return new Result(ResultType.TIMEOUT, 0);
-        var evaluator = new GraphEvaluator();
-        return evaluator.evaluate(start, parameter, loops);
-    }
-
-}
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.TypeInteger;
+
+import java.util.Arrays;
+import java.util.BitSet;
+import java.util.HashMap;
+
+public class GraphEvaluator {
+
+    public enum ResultType { VALUE, FALLTHROUGH, TIMEOUT }
+
+    public record Result(ResultType type, long value) {}
+
+    /**
+     * Find the start node from some node in the graph or null if there is no start node
+     */
+    private static StartNode findStart(BitSet visit, Node node) {
+        if (node == null) return null;
+        if (node instanceof StartNode start) return start;
+        if( visit.get(node._nid) ) return null;
+        visit.set(node._nid);
+        for( Node def : node._inputs ) {
+            var res = findStart(visit,def);
+            if( res != null ) return res;
+        }
+        for( Node use : node._outputs ) {
+            var res = findStart(visit,use);
+            if( res != null ) return res;
+        }
+        return null;
+    }
+
+    /**
+     * Find the control output from a control node
+     */
+    private static Node findControl(Node control) {
+        for( Node use : control._outputs ) {
+            if (use.isCFG()) return use;
+        }
+        return null;
+    }
+
+    /**
+     * Find the projection for a node
+     */
+    private static ProjNode findProjection(Node node, int idx) {
+        for( Node use : node._outputs ) {
+            if (use instanceof ProjNode proj && proj._idx == idx) return proj;
+        }
+        return null;
+    }
+
+    /**
+     * Cache values for phi and parameter projection nodes.
+     */
+    private final HashMap<Node, Long> cacheValues = new HashMap<>();
+    /**
+     * Cache for loop phis as they can depend on itself or other loop phis
+     */
+    private long[] loopPhiCache = new long[16];
+
+    private GraphEvaluator() {
+    }
+
+    private long div(DivNode div) {
+        long in2 = getValue(div.in(2));
+        return in2 == 0 ? 0 : getValue(div.in(1)) / in2;
+    }
+
+    /**
+     * Calculate the value of a node
+     */
+    private long getValue(Node node) {
+        var cache = cacheValues.get(node);
+        if (cache != null) return cache;
+        return switch (node) {
+            case ConstantNode cons  -> ((TypeInteger)cons.compute()).value();
+            case AddNode      add   -> getValue(add.in(1)) + getValue(add.in(2));
+            case BoolNode.EQ  eq    -> getValue(eq.in(1)) == getValue(eq.in(2)) ? 1 : 0;
+            case BoolNode.LE  le    -> getValue(le.in(1)) <= getValue(le.in(2)) ? 1 : 0;
+            case BoolNode.LT  lt    -> getValue(lt.in(1)) <  getValue(lt.in(2)) ? 1 : 0;
+            case DivNode      div   -> div(div);
+            case MinusNode    minus -> -getValue(minus.in(1));
+            case MulNode      mul   -> getValue(mul.in(1)) * getValue(mul.in(2));
+            case NotNode      not   -> getValue(not.in(1)) == 0 ? 1 : 0;
+            case SubNode      sub   -> getValue(sub.in(1)) - getValue(sub.in(2));
+            default                 -> throw Utils.TODO("Unexpected node " + node);
+        };
+    }
+
+    /**
+     * Special case of latchPhis when phis can depend on phis of the same region.
+     */
+    private void latchLoopPhis(RegionNode region, Node prev) {
+        int idx = Utils.find(region._inputs, prev);
+        assert idx > 0;
+        int i = 0;
+        for( Node use : region._outputs ) {
+            if (use instanceof PhiNode phi) {
+                var value = getValue(phi.in(idx));
+                if (i == loopPhiCache.length) loopPhiCache = Arrays.copyOf(loopPhiCache, loopPhiCache.length*2);
+                loopPhiCache[i++] = value;
+            }
+        }
+        i = 0;
+        for( Node use : region._outputs ) {
+            if (use instanceof PhiNode phi) cacheValues.put(phi, loopPhiCache[i++]);
+        }
+    }
+
+    /**
+     * Calculate the values of phis of the region and caches the values. The phis are not allowed to depend on other phis of the region.
+     */
+    private void latchPhis(RegionNode region, Node prev) {
+        int idx = Utils.find(region._inputs, prev);
+        assert idx > 0;
+        for( Node use : region._outputs ) {
+            if (use instanceof PhiNode phi) {
+                var value = getValue(phi.in(idx));
+                cacheValues.put(phi, value);
+            }
+        }
+    }
+
+    /**
+     * Run the graph until either a return is found or the number of loop iterations are done.
+     */
+    private Result evaluate(StartNode start, long parameter, int loops) {
+        var parameter1 = findProjection(start, 1);
+        if (parameter1 != null) cacheValues.put(parameter1, parameter);
+        Node control = findProjection(start, 0);
+        Node prev = start;
+        while (control != null) {
+            Node next;
+            switch (control) {
+                case RegionNode region -> {
+                    if (region instanceof LoopNode && region.in(1) != prev) {
+                        if (loops--<=0) return new Result(ResultType.TIMEOUT, 0);
+                        latchLoopPhis(region, prev);
+                    } else {
+                        latchPhis(region, prev);
+                    }
+                    next = findControl(region);
+                }
+                case IfNode cond -> next = findProjection(cond, getValue(cond.in(1)) != 0 ? 0 : 1);
+                case ReturnNode ret -> {
+                    return new Result(ResultType.VALUE, getValue(ret.in(1)));
+                }
+                case ProjNode ignored -> next = findControl(control);
+                default -> throw Utils.TODO("Unexpected control node " + control);
+            }
+            prev = control;
+            control = next;
+        }
+        return new Result(ResultType.FALLTHROUGH, 0);
+    }
+
+    public static long evaluate(Node graph) {
+        return evaluate(graph, 0);
+    }
+
+    public static long evaluate(Node graph, long parameter) {
+        return evaluate(graph, parameter, 1000);
+    }
+
+    public static long evaluate(Node graph, long parameter, int loops) {
+        var res = evaluateWithResult(graph, parameter, loops);
+        if (res.type==ResultType.TIMEOUT) throw new RuntimeException("Timeout");
+        return res.value;
+    }
+
+    public static Result evaluateWithResult(Node graph, long parameter, int loops) {
+        var start = findStart(new BitSet(), graph);
+        if (start == null) return new Result(ResultType.TIMEOUT, 0);
+        var evaluator = new GraphEvaluator();
+        return evaluator.evaluate(start, parameter, loops);
+    }
+
+}
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/GraphVisualizer.java b/chapter08/src/main/java/com/seaofnodes/simple/GraphVisualizer.java
index 5009264f..d75e5bea 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/GraphVisualizer.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/GraphVisualizer.java
@@ -30,7 +30,7 @@ public class GraphVisualizer {
         sb.append("/*\n");
         sb.append(parser.src());
         sb.append("\n*/\n");
-        
+
         // To keep the Scopes below the graph and pointing up into the graph we
         // need to group the Nodes in a subgraph cluster, and the scopes into a
         // different subgraph cluster.  THEN we can draw edges between the
@@ -50,7 +50,7 @@ public class GraphVisualizer {
 
         // Just the Nodes first, in a cluster no edges
         nodes(sb, all);
-        
+
         // Now the scopes, in a cluster no edges
         for( ScopeNode scope : parser._xScopes )
             scope( sb, scope );
@@ -61,7 +61,7 @@ public class GraphVisualizer {
         // Walk the active Scope edges
         for( ScopeNode scope : parser._xScopes )
             scopeEdges( sb, scope );
-        
+
         sb.append("}\n");
         return sb.toString();
     }
@@ -195,13 +195,13 @@ public class GraphVisualizer {
                         sb.append(" color=red");
                     // Backedges do not add a ranking constraint
                     if( i==2 && (n instanceof PhiNode || n instanceof LoopNode) )
-                        sb.append(" constraint=false");                        
+                        sb.append(" constraint=false");
                     sb.append("];\n");
                 }
             }
         }
     }
-    
+
     // Walk the scope edges
     private void scopeEdges( StringBuilder sb, ScopeNode scope ) {
         sb.append("\tedge [style=dashed color=cornflowerblue];\n");
@@ -228,7 +228,7 @@ public class GraphVisualizer {
             level++;
         }
     }
-    
+
     /**
      * Finds all nodes in the graph.
      */
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/Parser.java b/chapter08/src/main/java/com/seaofnodes/simple/Parser.java
index 45332396..d4b0c327 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/Parser.java
@@ -13,7 +13,7 @@ import java.util.*;
  * This is a simple recursive descent parser. All lexical analysis is done here as well.
  */
 public class Parser {
-  
+
     /**
      * A Global Static, unique to each compilation.  This is a public, so we
      * can make constants everywhere without having to thread the StartNode
@@ -57,7 +57,7 @@ public class Parser {
             add("while");
         }};
 
-    
+
     /**
      * We clone ScopeNodes when control flows branch; it is useful to have
      * a list of all active ScopeNodes for purposes of visualization of the SoN graph
@@ -82,12 +82,12 @@ public class Parser {
 
     @Override
     public String toString() { return _lexer.toString(); }
-  
+
     String src() { return new String( _lexer._input ); }
 
     // Debugging utility to find a Node by index
     public static Node find(int nid) { return START.find(nid); }
-    
+
     private Node ctrl() { return _scope.ctrl(); }
 
     private Node ctrl(Node n) { return _scope.ctrl(n); }
@@ -108,7 +108,7 @@ public class Parser {
         return STOP;
     }
 
-    
+
     /**
      * Parses a block
      *
@@ -199,7 +199,7 @@ public class Parser {
 
         // No continues yet
         _continueScope = null;
-        
+
         // Parse the true side, which corresponds to loop body
         // Our current scope is the body Scope
         ctrl(ifT);              // set ctrl token to ifTrue projection
@@ -283,7 +283,7 @@ public class Parser {
         ctrl(ifT);              // set ctrl token to ifTrue projection
         parseStatement();       // Parse true-side
         ScopeNode tScope = _scope;
-        
+
         // Parse the false side
         _scope = fScope;        // Restore scope, then parse else block if any
         ctrl(ifF);              // Ctrl token is now set to ifFalse projection
@@ -294,7 +294,7 @@ public class Parser {
 
         if( tScope.nIns() != ndefs || fScope.nIns() != ndefs )
             throw error("Cannot define a new name on one arm of an if");
-        
+
         // Merge results
         _scope = tScope;
         _xScopes.pop();       // Discard pushed from graph display
@@ -583,7 +583,7 @@ public class Parser {
             skipWhiteSpace();
             return peek()==ch;
         }
-        
+
         // Return an identifier or null
         String matchId() {
             skipWhiteSpace();
@@ -610,7 +610,7 @@ public class Parser {
             return TypeInteger.constant(Long.parseLong(snum));
         }
 
-        // First letter of an identifier 
+        // First letter of an identifier
         private boolean isIdStart(char ch) {
             return Character.isAlphabetic(ch) || ch == '_';
         }
@@ -626,7 +626,7 @@ public class Parser {
             return new String(_input, start, --_position - start);
         }
 
-        // 
+        //
         private boolean isPunctuation(char ch) {
             return "=;[]<>()+-/*".indexOf(ch) != -1;
         }
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/Utils.java b/chapter08/src/main/java/com/seaofnodes/simple/Utils.java
index 4d663c25..45f15327 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/Utils.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/Utils.java
@@ -36,4 +36,4 @@ public class Utils {
                 return i;
         return -1;
     }
-}
\ No newline at end of file
+}
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/AddNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/AddNode.java
index 5878f340..84a368fd 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/AddNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/AddNode.java
@@ -8,7 +8,7 @@ public class AddNode extends Node {
     public AddNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
 
     @Override public String label() { return "Add"; }
-    
+
     @Override public String glabel() { return "+"; }
 
     @Override
@@ -17,7 +17,7 @@ public class AddNode extends Node {
         in(2)._print0(sb.append("+"), visited);
         return sb.append(")");
     }
-  
+
 
     @Override
     public Type compute() {
@@ -44,13 +44,13 @@ public class AddNode extends Node {
         // canonicalize to (x+0)
         if( t2 instanceof TypeInteger i && i.value()==0 )
             return lhs;
-              
+
         // Add of same to a multiply by 2
         if( lhs==rhs )
             return new MulNode(lhs,new ConstantNode(TypeInteger.constant(2)).peephole());
 
         // Goal: a left-spine set of adds, with constants on the rhs (which then fold).
-        
+
         // Move non-adds to RHS
         if( !(lhs instanceof AddNode) && rhs instanceof AddNode )
             return swap12();
@@ -74,7 +74,7 @@ public class AddNode extends Node {
         // the loop will peep as dead after a bit.
         if( lhs.in(1) == lhs )
             return null;
-        
+
         // Do we have (x + con1) + con2?
         // Replace with (x + (con1+con2) which then fold the constants
         if( lhs.in(2)._type.isConstant() && t2.isConstant() )
@@ -88,12 +88,12 @@ public class AddNode extends Node {
         if( phicon!=null ) return phicon;
 
         // Now we sort along the spline via rotates, to gather similar things together.
-        
+
         // Do we rotate (x + y) + z
         // into         (x + z) + y ?
         if( spline_cmp(lhs.in(2),rhs) )
             return new AddNode(new AddNode(lhs.in(1),rhs).peephole(),lhs.in(2));
-        
+
         return null;
     }
 
@@ -111,11 +111,11 @@ public class AddNode extends Node {
             lphi = pcon(lhs.in(2)); // Will rotate with the Phi push
         }
         if( lphi==null ) return null;
-        
+
         // RHS is a constant or a Phi of constants
         if( !(rhs instanceof ConstantNode con) && pcon(rhs)==null )
             return null;
-        
+
         // If both are Phis, must be same Region
         if( rhs instanceof PhiNode && lphi.in(0) != rhs.in(0) )
             return null;
@@ -137,7 +137,7 @@ public class AddNode extends Node {
     static PhiNode pcon(Node op) {
         return op instanceof PhiNode phi && phi.allCons() ? phi : null;
     }
-        
+
     // Compare two off-spline nodes and decide what order they should be in.
     // Do we rotate ((x + hi) + lo) into ((x + lo) + hi) ?
     // Generally constants always go right, then Phi-of-constants, then muls, then others.
@@ -146,16 +146,16 @@ public class AddNode extends Node {
     static boolean spline_cmp( Node hi, Node lo ) {
         if( lo._type.isConstant() ) return false;
         if( hi._type.isConstant() ) return true ;
-            
+
         if( lo instanceof PhiNode && lo.allCons() ) return false;
         if( hi instanceof PhiNode && hi.allCons() ) return true ;
 
         if( lo instanceof PhiNode && !(hi instanceof PhiNode) ) return true;
         if( hi instanceof PhiNode && !(lo instanceof PhiNode) ) return false;
-        
+
         // Same category of "others"
         return lo._nid > hi._nid;
     }
-    
+
     @Override Node copy(Node lhs, Node rhs) { return new AddNode(lhs,rhs); }
 }
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/BoolNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/BoolNode.java
index d65fbf14..0c32d50d 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/BoolNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/BoolNode.java
@@ -12,7 +12,7 @@ abstract public class BoolNode extends Node {
     }
 
     abstract String op();       // String opcode name
-    
+
     @Override
     public String label() { return getClass().getSimpleName(); }
 
@@ -41,7 +41,7 @@ abstract public class BoolNode extends Node {
 
     @Override
     public Node idealize() {
-        // Compare of same 
+        // Compare of same
         if( in(1)==in(2) )
             return new ConstantNode(TypeInteger.constant(doOp(3,3)?1:0));
 
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/ConstantNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/ConstantNode.java
index 0e13d2f2..13006bfb 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/ConstantNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/ConstantNode.java
@@ -23,10 +23,10 @@ public class ConstantNode extends Node {
         super(Parser.START);
         _con = type;
     }
-    
+
     @Override
     public String label() { return ""+_con; }
-  
+
     @Override
     public String uniqueName() { return "Con_" + _nid; }
 
@@ -34,9 +34,9 @@ public class ConstantNode extends Node {
     StringBuilder _print1(StringBuilder sb, BitSet visited) {
         return _con._print(sb);
     }
-    
+
     @Override public boolean isMultiTail() { return true; }
-    
+
     @Override
     public Type compute() { return _con; }
 
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/DivNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/DivNode.java
index b0e12547..2213d2e7 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/DivNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/DivNode.java
@@ -18,7 +18,7 @@ public class DivNode extends Node {
         in(2)._print0(sb.append("/"), visited);
         return sb.append(")");
     }
-  
+
     @Override
     public Type compute() {
         if (in(1)._type instanceof TypeInteger i0 &&
@@ -34,6 +34,6 @@ public class DivNode extends Node {
 
     @Override
     public Node idealize() { return null; }
-  
+
     @Override Node copy(Node lhs, Node rhs) { return new DivNode(lhs,rhs); }
 }
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/IfNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/IfNode.java
index 1d1da4fa..23a8fafc 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/IfNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/IfNode.java
@@ -47,7 +47,7 @@ public class IfNode extends MultiNode {
               // Repeated test, dominated on one side.  Test result is the same.
               ? (proj._idx==0 ? TypeTuple.IF_TRUE : TypeTuple.IF_FALSE)
               : dom._type;      // Repeated test not dominated on one side
-        
+
         return TypeTuple.IF_BOTH;
     }
 
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/LoopNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/LoopNode.java
index 0b84f897..c192bc20 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/LoopNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/LoopNode.java
@@ -25,5 +25,5 @@ public class LoopNode extends RegionNode {
         return inProgress() ? null : super.idealize();
     }
 
-    @Override Node idom() { return entry(); }    
+    @Override Node idom() { return entry(); }
 }
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/MinusNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/MinusNode.java
index 8a96693d..3d944fd4 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/MinusNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/MinusNode.java
@@ -9,15 +9,15 @@ public class MinusNode extends Node {
     public MinusNode(Node in) { super(null, in); }
 
     @Override public String label() { return "Minus"; }
-  
+
     @Override public String glabel() { return "-"; }
-  
+
     @Override
     StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("(-"), visited);
         return sb.append(")");
     }
-  
+
     @Override
     public Type compute() {
         if (in(1)._type instanceof TypeInteger i0)
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/MulNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/MulNode.java
index 70e6c0db..2e701a4e 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/MulNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/MulNode.java
@@ -9,7 +9,7 @@ public class MulNode extends Node {
     public MulNode(Node lhs, Node rhs) { super(null, lhs, rhs); }
 
     @Override public String label() { return "Mul"; }
-  
+
     @Override public String glabel() { return "*"; }
 
     @Override
@@ -36,12 +36,12 @@ public class MulNode extends Node {
         Node rhs = in(2);
         Type t1 = lhs._type;
         Type t2 = rhs._type;
-        
+
         // Mul of 1.  We do not check for (1*x) because this will already
         // canonicalize to (x*1)
         if ( t2.isConstant() && t2 instanceof TypeInteger i && i.value()==1 )
             return lhs;
-        
+
         // Move constants to RHS: con*arg becomes arg*con
         if ( t1.isConstant() && !t2.isConstant() )
             return swap12();
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/MultiNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/MultiNode.java
index 81c90f68..7ba1aa19 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/MultiNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/MultiNode.java
@@ -1,7 +1,7 @@
 package com.seaofnodes.simple.node;
 
 public abstract class MultiNode extends Node {
-    
+
     public MultiNode(Node... inputs) { super(inputs); }
 
 }
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/Node.java b/chapter08/src/main/java/com/seaofnodes/simple/node/Node.java
index fd312c3d..2d6d5ad5 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/Node.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/Node.java
@@ -47,7 +47,7 @@ public abstract class Node {
      */
     public Type _type;
 
-    
+
     /**
      * Immediate dominator tree depth, used to approximate a real IDOM during
      * parsing where we do not have the whole program, and also peepholes
@@ -56,7 +56,7 @@ public abstract class Node {
      * See {@link <a href="https://en.wikipedia.org/wiki/Dominator_(graph_theory)">...</a>}
      */
     int _idepth;
-    
+
     /**
      * A private Global Static mutable counter, for unique node id generation.
      * To make the compiler multithreaded, this field will have to move into a TLS.
@@ -85,9 +85,9 @@ public abstract class Node {
 
 
     // ------------------------------------------------------------------------
-    
+
     // Debugger Printing.
-    
+
     // {@code toString} is what you get in the debugger.  It has to print 1
     // line (because this is what a debugger typically displays by default) and
     // has to be robust with broken graph/nodes.
@@ -101,7 +101,7 @@ public abstract class Node {
     public final String print() {
         return _print0(new StringBuilder(), new BitSet()).toString();
     }
-    
+
     // This is the common print: check for repeats, check for DEAD and print
     // "DEAD" else call the per-Node print1.
     final StringBuilder _print0(StringBuilder sb, BitSet visited) {
@@ -141,13 +141,13 @@ public abstract class Node {
     }
 
     public String p(int depth) { return IRPrinter.prettyPrint(this,depth); }
-    
+
     public boolean isMultiHead() { return false; }
     public boolean isMultiTail() { return false; }
-    
+
     // ------------------------------------------------------------------------
     // Graph Node & Edge manipulation
-    
+
     /**
      * Gets the ith input node
      * @param i Offset of the input node
@@ -162,19 +162,19 @@ public abstract class Node {
     public boolean isUnused() { return nOuts() == 0; }
 
     public boolean isCFG() { return false; }
-  
+
     /**
      * Change a <em>def</em> into a Node.  Keeps the edges correct, by removing
      * the corresponding <em>use->def</em> edge.  This may make the original
      * <em>def</em> go dead.  This function is co-recursive with {@link #kill}.
      * <p>
-     
+
      * This method is the normal path for altering a Node, because it does the
      * proper default edge maintenance.  It also <em>immediately</em> kills
      * Nodes that lose their last use; at times care must be taken to avoid
      * killing Nodes that are being used without having an output Node.  This
      * definitely happens in the middle of recursive {@link #peephole} calls.
-     *     
+     *
      * @param idx which def to set
      * @param new_def the new definition
      * @return new_def for flow coding
@@ -195,7 +195,7 @@ public abstract class Node {
         // Return self for easy flow-coding
         return new_def;
     }
-  
+
     // Remove the numbered input, compressing the inputs in-place.  This
     // shuffles the order deterministically - which is suitable for Region and
     // Phi, but not for every Node.
@@ -244,7 +244,7 @@ public abstract class Node {
                 old_def.kill();        // Kill old def
         }
     }
-  
+
     /**
      * Kill a Node with no <em>uses</em>, by setting all of its <em>defs</em>
      * to null.  This may recursively kill more Nodes and is basically dead
@@ -278,10 +278,10 @@ public abstract class Node {
         }
         kill();
     }
-    
+
     // ------------------------------------------------------------------------
     // Graph-based optimizations
-    
+
     /**
      * We allow disabling peephole opt so that we can observe the
      * full graph, vs the optimized graph.
@@ -306,7 +306,7 @@ public abstract class Node {
     public final Node peephole( ) {
         // Compute initial or improved Type
         Type type = _type = compute();
-        
+
         if (_disablePeephole)
             return this;        // Peephole optimizations turned off
 
@@ -315,13 +315,13 @@ public abstract class Node {
             return deadCodeElim(new ConstantNode(type).peephole());
 
         // Future chapter: Global Value Numbering goes here
-        
+
         // Ask each node for a better replacement
         Node n = idealize();
         if( n != null )         // Something changed
             // Recursively optimize
             return deadCodeElim(n.peephole());
-        
+
         return this;            // No progress
     }
 
@@ -341,7 +341,7 @@ public abstract class Node {
         }
         return m;
     }
-  
+
     /**
      * This function needs to be
      * <a href="https://en.wikipedia.org/wiki/Monotonic_function">Monotonic</a>
@@ -410,7 +410,7 @@ public abstract class Node {
 
     // ------------------------------------------------------------------------
     // Peephole utilities
-    
+
     // Swap inputs without letting either input go dead during the swap.
     Node swap12() {
         Node tmp = in(1);
@@ -418,7 +418,7 @@ public abstract class Node {
         _inputs.set(2,tmp);
         return this;
     }
-    
+
     // does this node contain all constants?
     // Ignores in(0), as is usually control.
     boolean allCons() {
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/NotNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/NotNode.java
index 04e6c75b..39df410d 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/NotNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/NotNode.java
@@ -9,15 +9,15 @@ public class NotNode extends Node {
     public NotNode(Node in) { super(null, in); }
 
     @Override public String label() { return "Not"; }
-  
+
     @Override public String glabel() { return "!"; }
-  
+
     @Override
     StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("(!"), visited);
         return sb.append(")");
     }
-  
+
     @Override
     public Type compute() {
         if( in(1)._type instanceof TypeInteger i0 )
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/PhiNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/PhiNode.java
index 975630d0..c7b5b357 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/PhiNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/PhiNode.java
@@ -7,7 +7,7 @@ import java.util.BitSet;
 public class PhiNode extends Node {
 
     final String _label;
-    
+
     public PhiNode(String label, Node... inputs) { super(inputs); _label = label; }
 
     @Override public String label() { return "Phi_"+_label; }
@@ -35,7 +35,7 @@ public class PhiNode extends Node {
     @Override
     public Type compute() {
         if( !(region() instanceof RegionNode r) || r.inProgress() )
-            return Type.BOTTOM;            
+            return Type.BOTTOM;
         Type t = Type.TOP;
         for (int i = 1; i < nIns(); i++)
             t = t.meet(in(i)._type);
@@ -53,7 +53,7 @@ public class PhiNode extends Node {
             return live;
 
         // Pull "down" a common data op.  One less op in the world.  One more
-        // Phi, but Phis do not make code.        
+        // Phi, but Phis do not make code.
         //   Phi(op(A,B),op(Q,R),op(X,Y)) becomes
         //     op(Phi(A,Q,X), Phi(B,R,Y)).
         Node op = in(1);
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/ProjNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/ProjNode.java
index 79ba9d13..c263502d 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/ProjNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/ProjNode.java
@@ -12,7 +12,7 @@ public class ProjNode extends Node {
 
     // Debugging label
     public final String _label;
-    
+
     public ProjNode(MultiNode ctrl, int idx, String label) {
         super(ctrl);
         _idx = idx;
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/RegionNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/RegionNode.java
index 00c010b2..453d028f 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/RegionNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/RegionNode.java
@@ -9,7 +9,7 @@ import java.util.BitSet;
 public class RegionNode extends Node {
 
     public RegionNode(Node... nodes) { super(nodes); }
-    
+
     @Override
     public String label() { return "Region"; }
 
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/ReturnNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/ReturnNode.java
index 4dea773a..312058b9 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/ReturnNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/ReturnNode.java
@@ -21,7 +21,7 @@ public class ReturnNode extends Node {
 
     public Node ctrl() { return in(0); }
     public Node expr() { return in(1); }
-  
+
     @Override
     public String label() { return "Return"; }
 
@@ -31,7 +31,7 @@ public class ReturnNode extends Node {
     }
 
     @Override public boolean isCFG() { return true; }
-  
+
     @Override
     public Type compute() {
         return new TypeTuple(ctrl()._type,expr()._type);
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/ScopeNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/ScopeNode.java
index a6a7f536..e5d03d93 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/ScopeNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/ScopeNode.java
@@ -28,8 +28,8 @@ public class ScopeNode extends Node {
         _scopes = new Stack<>();
         _type = Type.BOTTOM;
     }
-    
-    
+
+
     @Override public String label() { return "Scope"; }
 
     @Override
@@ -63,7 +63,7 @@ public class ScopeNode extends Node {
                 names[syms.get(name)] = name;
         return names;
     }
-    
+
     @Override public Type compute() { return Type.BOTTOM; }
 
     @Override public Node idealize() { return null; }
@@ -190,7 +190,7 @@ public class ScopeNode extends Node {
         that.kill();            // Kill merged scope
         return r.unkeep().peephole();
     }
-    
+
     // Merge the backedge scope into this loop head scope
     // We set the second input to the phi from the back edge (i.e. loop body)
     public void endLoop(ScopeNode back, ScopeNode exit ) {
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/StartNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/StartNode.java
index 19d03e0f..01f1485a 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/StartNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/StartNode.java
@@ -15,7 +15,7 @@ import java.util.BitSet;
 public class StartNode extends MultiNode {
 
     final TypeTuple _args;
-    
+
     public StartNode(Type[] args) {
         super();
         _args = new TypeTuple(args);
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/StopNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/StopNode.java
index a0aacf2b..417790d9 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/StopNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/StopNode.java
@@ -30,7 +30,7 @@ public class StopNode extends Node {
     public ReturnNode ret() {
         return nIns()==1 ? (ReturnNode)in(0) : null;
     }
-    
+
     @Override
     public Type compute() {
         return Type.BOTTOM;
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/node/SubNode.java b/chapter08/src/main/java/com/seaofnodes/simple/node/SubNode.java
index 1484ab8a..4a06fcb3 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/node/SubNode.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/node/SubNode.java
@@ -18,7 +18,7 @@ public class SubNode extends Node {
         in(2)._print0(sb.append("-"), visited);
         return sb.append(")");
     }
-  
+
     @Override
     public Type compute() {
         if (in(1)._type instanceof TypeInteger i0 &&
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/type/Type.java b/chapter08/src/main/java/com/seaofnodes/simple/type/Type.java
index f88403a5..2f0e6171 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/type/Type.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/type/Type.java
@@ -4,7 +4,7 @@ package com.seaofnodes.simple.type;
 /**
  * These types are part of a Monotone Analysis Framework,
  * @see <a href="https://www.cse.psu.edu/~gxt29/teaching/cse597s21/slides/08monotoneFramework.pdf">see for example this set of slides</a>.
- * <p> 
+ * <p>
  * The types form a lattice; @see <a href="https://en.wikipedia.org/wiki/Lattice_(order)">a symmetric complete bounded (ranked) lattice.</a>
  * <p>
  * This wild lattice theory will be needed later to allow us to easily beef up
@@ -15,7 +15,7 @@ package com.seaofnodes.simple.type;
  * actual implementation is darn near trivial and is generally really obvious
  * what we're doing with it.  Right now, it's just simple integer math to do
  * simple constant folding e.g. 1+2 == 3 stuff.
- */    
+ */
 
 public class Type {
 
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/type/TypeInteger.java b/chapter08/src/main/java/com/seaofnodes/simple/type/TypeInteger.java
index 93f5eae3..b30e21d8 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/type/TypeInteger.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/type/TypeInteger.java
@@ -28,7 +28,7 @@ public class TypeInteger extends Type {
     public boolean isTop() { return !_is_con && _con==0; }
     public boolean isBot() { return !_is_con && _con==1; }
 
-    @Override 
+    @Override
     public StringBuilder _print(StringBuilder sb) {
         if (isTop()) return sb.append("IntTop");
         if (isBot()) return sb.append("IntBot");
diff --git a/chapter08/src/main/java/com/seaofnodes/simple/type/TypeTuple.java b/chapter08/src/main/java/com/seaofnodes/simple/type/TypeTuple.java
index f8c3b3c8..0f8b95bd 100644
--- a/chapter08/src/main/java/com/seaofnodes/simple/type/TypeTuple.java
+++ b/chapter08/src/main/java/com/seaofnodes/simple/type/TypeTuple.java
@@ -1,7 +1,7 @@
 package com.seaofnodes.simple.type;
 
 public class TypeTuple extends Type {
-  
+
     public final Type[] _types;
 
     public TypeTuple(Type... _types) {
diff --git a/chapter08/src/test/java/com/seaofnodes/simple/Chapter08Test.java b/chapter08/src/test/java/com/seaofnodes/simple/Chapter08Test.java
index 3df49f4a..f8bbfaa3 100644
--- a/chapter08/src/test/java/com/seaofnodes/simple/Chapter08Test.java
+++ b/chapter08/src/test/java/com/seaofnodes/simple/Chapter08Test.java
@@ -154,10 +154,10 @@ return arg;
         StopNode stop = parser.parse(true);
         assertEquals("Stop[ return 0; return 0; ]", stop.toString());
     }
-    
+
     @Test
     public void testChapter8BreakOutsideLoop() {
-        try { 
+        try {
             new Parser("""
 if(arg <= 10) {
     break;
@@ -182,7 +182,7 @@ return arg;
         StopNode stop = parser.parse(true);
         assertEquals("return arg;", stop.toString());
     }
-        
+
     @Test
     public void testChapter8Regress4() {
         Parser parser = new Parser("""
@@ -198,9 +198,9 @@ return a;
 """);
         StopNode stop = parser.parse(true);
         assertEquals("return Phi(Region28,Phi(Loop7,1,(Phi_a+1)),Add);", stop.toString());
-        assertTrue(stop.ret().ctrl() instanceof RegionNode);                   
+        assertTrue(stop.ret().ctrl() instanceof RegionNode);
     }
-        
+
     @Test
     public void testChapter8Regress5() {
         Parser parser = new Parser("""
@@ -216,7 +216,7 @@ return a;
         assertEquals("return (Phi(Loop7,1,Add)+1);", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof RegionNode);
     }
-        
+
     @Test
     public void testChapter7Example() {
         Parser parser = new Parser(
@@ -250,7 +250,7 @@ return a;
         StopNode stop = parser.parse(true);
         assertEquals("return Phi(Region22,1,Phi(Loop11,1,(Phi_a+1)));", stop.toString());
     }
-  
+
     @Test
     public void testChapter7WhileNested() {
         Parser parser = new Parser(
@@ -749,7 +749,7 @@ return a;""");
         StopNode ret = parser.parse(true);
         assertEquals("return Phi(Region17,(arg+2),(arg-3));", ret.toString());
     }
-  
+
     @Test
     public void testChapter5Test() {
         Parser parser = new Parser(
@@ -764,20 +764,20 @@ return c;""", TypeInteger.BOT);
         StopNode ret = parser.parse(true);
         assertEquals("return Phi(Region16,4,3);", ret.toString());
     }
-    
+
     @Test
     public void testChapter5Return2() {
         Parser parser = new Parser(
 """
-if( arg==1 ) 
-    return 3; 
-else 
-    return 4; 
+if( arg==1 )
+    return 3;
+else
+    return 4;
 #showGraph;""", TypeInteger.BOT);
         StopNode stop = parser.parse();
         assertEquals("Stop[ return 3; return 4; ]", stop.toString());
     }
-    
+
     @Test
     public void testChapter5IfMergeB() {
         Parser parser = new Parser(
@@ -863,20 +863,20 @@ return a;""");
       StopNode stop = new Parser("return true;").parse();
       assertEquals("return 1;",stop.toString());
     }
-    
+
     @Test
     public void testChapter5HalfDef() {
-        try { 
+        try {
             new Parser("if( arg==1 ) int b=2; return b;").parse();
             fail();
         } catch( RuntimeException e ) {
             assertEquals("Cannot define a new name on one arm of an if",e.getMessage());
         }
     }
-    
+
     @Test
     public void testChapter5HalfDef2() {
-        try { 
+        try {
             new Parser("if( arg==1 ) { int b=2; } else { int b=3; } return b;").parse();
             fail();
         } catch( RuntimeException e ) {
@@ -886,38 +886,38 @@ return a;""");
 
     @Test
     public void testChapter5Regress1() {
-        try { 
+        try {
             new Parser("if(arg==2) int a=1; else int b=2; return a;").parse();
             fail();
         } catch( RuntimeException e ) {
             assertEquals("Cannot define a new name on one arm of an if",e.getMessage());
         }
     }
-    
+
 
     @Test
     public void testChapter5BadNum() {
-        try { 
+        try {
             new Parser("return 1-;").parse();
             fail();
         } catch( RuntimeException e ) {
             assertEquals("Syntax error, expected an identifier or expression: ;",e.getMessage());
         }
     }
-      
+
     @Test
     public void testChapter5Keyword1() {
-        try { 
+        try {
             new Parser("int true=0; return true;").parse();
             fail();
         } catch( RuntimeException e ) {
             assertEquals("Expected an identifier, found 'true'",e.getMessage());
         }
     }
-      
+
     @Test
     public void testChapter5Keyword2() {
-        try { 
+        try {
             new Parser("int else=arg; if(else) else=2; else else=1; return else;").parse();
             fail();
         } catch( RuntimeException e ) {
@@ -927,14 +927,14 @@ return a;""");
 
     @Test
         public void testChapter5Keyword3() {
-        try { 
+        try {
             new Parser("int a=1; ififif(arg)inta=2;return a;").parse();
             fail();
         } catch( RuntimeException e ) {
             assertEquals("Syntax error, expected =: (",e.getMessage());
         }
     }
-    
+
     @Test
     public void testChapter4Peephole() {
         Parser parser = new Parser("return 1+arg+2; #showGraph;");
@@ -962,7 +962,7 @@ return a;""");
         StopNode ret = parser.parse();
         assertEquals("return (arg*2);", ret.print());
     }
-  
+
     @Test
     public void testChapter4Peephole3() {
         Parser parser = new Parser("return 1+arg+2+arg+3; #showGraph;");
@@ -976,7 +976,7 @@ return a;""");
         StopNode ret = parser.parse();
         assertEquals("return arg;", ret.print());
     }
-  
+
     @Test
     public void testChapter4VarArg() {
         Parser parser = new Parser("return arg; #showGraph;");
@@ -1037,7 +1037,7 @@ return a;""");
 
     @Test
     public void testChapter4Bug3() {
-        try { 
+        try {
             new Parser("inta=1; return a;").parse();
             fail();
         } catch( RuntimeException e ) {
@@ -1051,7 +1051,7 @@ return a;""");
         StopNode ret = parser.parse();
         assertEquals("return (-arg);", ret.print());
     }
-    
+
     @Test
     public void testVarDecl() {
         Parser parser = new Parser("int a=1; return a;");
@@ -1091,7 +1091,7 @@ return a;""");
 
     @Test
     public void testSelfAssign() {
-        try { 
+        try {
             new Parser("int a=a; return a;").parse();
             fail();
         } catch( RuntimeException e ) {
@@ -1160,7 +1160,7 @@ return a;""");
         StopNode stop = parser.parse();
         StartNode start = Parser.START;
         ReturnNode ret = (ReturnNode)stop.in(0);
-        
+
         assertTrue(ret.ctrl() instanceof ProjNode);
         Node expr = ret.expr();
         if( expr instanceof ConstantNode con ) {
@@ -1183,7 +1183,7 @@ return a;""");
 
     @Test
     public void testBad1() {
-        try { 
+        try {
             new Parser("ret").parse();
             fail();
         } catch( RuntimeException e ) {
@@ -1193,7 +1193,7 @@ return a;""");
 
     @Test
     public void testBad2() {
-        try { 
+        try {
             new Parser("return 0123;").parse();
             fail();
         } catch( RuntimeException e ) {
@@ -1209,7 +1209,7 @@ return a;""");
 
     @Test
     public void testBad4() {
-        try { 
+        try {
             new Parser("return 100").parse();
             fail();
         } catch( RuntimeException e ) {
diff --git a/chapter08/src/test/java/com/seaofnodes/simple/Fuzzer08Test.java b/chapter08/src/test/java/com/seaofnodes/simple/Fuzzer08Test.java
index b8c0a8e5..ee635c22 100644
--- a/chapter08/src/test/java/com/seaofnodes/simple/Fuzzer08Test.java
+++ b/chapter08/src/test/java/com/seaofnodes/simple/Fuzzer08Test.java
@@ -1,26 +1,26 @@
-package com.seaofnodes.simple;
-
-import com.seaofnodes.simple.fuzzer.Fuzzer;
-import org.junit.Ignore;
-import org.junit.Test;
-
-
-import static org.junit.Assert.assertTrue;
-
-/**
- * To use the fuzzer run the <code>fuzzPeeps</code> methods.
- * This can be done from IntelliJ Gui or remove the `@Ignore` annotation and start the test case from the command line
- * via <code>mvn clean test -Dtest=com.seaofnodes.simple.Fuzzer08Test#fuzzPeeps</code>
- */
-public class Fuzzer08Test {
-
-    @Test
-    @Ignore
-    public void fuzzPeeps() {
-        var fuzzer = new Fuzzer();
-        for (int i=0; i<100000; i++)
-            fuzzer.fuzzPeeps(i);
-        assertTrue(fuzzer.noExceptions());
-    }
-
-}
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.fuzzer.Fuzzer;
+import org.junit.Ignore;
+import org.junit.Test;
+
+
+import static org.junit.Assert.assertTrue;
+
+/**
+ * To use the fuzzer run the <code>fuzzPeeps</code> methods.
+ * This can be done from IntelliJ Gui or remove the `@Ignore` annotation and start the test case from the command line
+ * via <code>mvn clean test -Dtest=com.seaofnodes.simple.Fuzzer08Test#fuzzPeeps</code>
+ */
+public class Fuzzer08Test {
+
+    @Test
+    @Ignore
+    public void fuzzPeeps() {
+        var fuzzer = new Fuzzer();
+        for (int i=0; i<100000; i++)
+            fuzzer.fuzzPeeps(i);
+        assertTrue(fuzzer.noExceptions());
+    }
+
+}
diff --git a/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java b/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java
index 2af22f1d..5fcd8764 100644
--- a/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java
+++ b/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/Fuzzer.java
@@ -1,128 +1,128 @@
-package com.seaofnodes.simple.fuzzer;
-
-import com.seaofnodes.simple.GraphEvaluator;
-import com.seaofnodes.simple.node.StopNode;
-
-import java.util.ArrayList;
-import java.util.Random;
-import java.util.function.Consumer;
-
-/**
- * Implementation of the fuzzer.
- * Random testcases are generated using the ScriptGenerator.
- * This will generate a script similar to how the parser parses it but instead of parsing it will
- * randomly choose a variation the parser would parse and generate it.
- * These scripts are the parsed by the parser and all exceptions are caught and filtered
- * to only show one occurrence of one problem. This includes script which generate different
- * results when the compiled graph with and without peeps is executed.
- * To aid debugging scripts that cause errors are then reduced by applying rules and checking
- * that the same issue persists.
- */
-public class Fuzzer {
-
-    private static final int EVAL_TIMEOUT = 1000;
-
-    /**
-     * List of exceptions already encountered.
-     * This is used to filter new exceptions and discard them if they are already found.
-     */
-    private final ArrayList<Throwable> exceptions = new ArrayList<>();
-
-    /**
-     * Filter and record an exception in a script.
-     * @param e The exception caused by the script
-     * @param script The script causing the exception
-     * @param reproducer Reproducer which should be used to reproduce the test case.
-     */
-    private void recordException(Throwable e, String script, Consumer<String> reproducer) {
-        for (var ex : exceptions) {
-            if (FuzzerUtils.isExceptionFromSameCause(ex, e)) return;
-        }
-        exceptions.add(e);
-        System.out.println("========== Stack ==========");
-        e.printStackTrace(System.out);
-        System.out.println("========== Code ===========");
-        System.out.println(script);
-        System.out.println("========= Reduced =========");
-        System.out.println(Reducer.reduce(script, e, reproducer));
-        System.out.println("===========================");
-        System.out.flush();
-    }
-
-    /**
-     * Check that two graphs result in the same output when supplied with a value
-     * @param stop1 Stop node of the first graph
-     * @param stop2 Stop node of the second graph
-     * @param in The input value to both graphs to test for an equal output
-     */
-    private static void checkGraphs(StopNode stop1, StopNode stop2, long in) {
-        var e1 = GraphEvaluator.evaluateWithResult(stop1, in, EVAL_TIMEOUT);
-        var e2 = GraphEvaluator.evaluateWithResult(stop2, in, EVAL_TIMEOUT);
-        if (e1.type() == GraphEvaluator.ResultType.TIMEOUT || e2.type() == GraphEvaluator.ResultType.TIMEOUT) return;
-        if (e1.type() != e2.type())
-            throw new RuntimeException("Different calculations types " + e1.type() + " vs " + e2.type());
-        if (e1.value() != e2.value())
-            throw new RuntimeException("Different calculations values " + e1.value() + " vs " + e2.value());
-    }
-
-    /**
-     * Run checks for script. Compile the script with peeps enabled and disabled.
-     * Check that exceptions raised in the parser by both methods are the same and only happens if the script may be invalid.
-     * If the script was successfully parsed check that both version behave the same.
-     * @param script The script to test
-     * @param valid If the script is definitely valid. If not some exceptions may be suppressed.
-     */
-    private static void runCheck(String script, boolean valid) {
-        StopNode stop1;
-        try {
-            stop1 = FuzzerUtils.parse(script, false);
-        } catch (RuntimeException e1) {
-            try {
-                FuzzerUtils.parse(script, true);
-            } catch (RuntimeException e2) {
-                if (FuzzerUtils.isExceptionFromSameCause(e1, e2)) {
-                    if (!valid || e1.getClass() == RuntimeException.class) return;
-                } else {
-                    e1.addSuppressed(e2);
-                }
-            }
-            throw e1;
-        }
-        var stop2 = FuzzerUtils.parse(script, true);
-        checkGraphs(stop1, stop2, 0);
-        checkGraphs(stop1, stop2, 1);
-        checkGraphs(stop1, stop2, 10);
-    }
-
-    /**
-     * Check that the script does not result in exceptions.
-     * @param script The script to test.
-     * @param valid If the script is valid or if it might contain syntax errors.
-     */
-    private void check(String script, boolean valid) {
-        try {
-            runCheck(script, valid);
-        } catch (Throwable e) {
-            recordException(e, script, s->runCheck(s, valid));
-        }
-    }
-
-    /**
-     * Run one test with the given seed.
-     * @param seed The seed to use for generating this test case
-     */
-    public void fuzzPeeps(long seed) {
-        var rand = new Random(seed);
-        var sb = new StringBuilder();
-        var valid = new ScriptGenerator(rand, sb, false).genProgram();
-        check(sb.toString(), valid);
-    }
-
-    /**
-     * Check that no exceptions happened.
-     * @return true if no exception happened
-     */
-    public boolean noExceptions() {
-        return exceptions.isEmpty();
-    }
-}
+package com.seaofnodes.simple.fuzzer;
+
+import com.seaofnodes.simple.GraphEvaluator;
+import com.seaofnodes.simple.node.StopNode;
+
+import java.util.ArrayList;
+import java.util.Random;
+import java.util.function.Consumer;
+
+/**
+ * Implementation of the fuzzer.
+ * Random testcases are generated using the ScriptGenerator.
+ * This will generate a script similar to how the parser parses it but instead of parsing it will
+ * randomly choose a variation the parser would parse and generate it.
+ * These scripts are the parsed by the parser and all exceptions are caught and filtered
+ * to only show one occurrence of one problem. This includes script which generate different
+ * results when the compiled graph with and without peeps is executed.
+ * To aid debugging scripts that cause errors are then reduced by applying rules and checking
+ * that the same issue persists.
+ */
+public class Fuzzer {
+
+    private static final int EVAL_TIMEOUT = 1000;
+
+    /**
+     * List of exceptions already encountered.
+     * This is used to filter new exceptions and discard them if they are already found.
+     */
+    private final ArrayList<Throwable> exceptions = new ArrayList<>();
+
+    /**
+     * Filter and record an exception in a script.
+     * @param e The exception caused by the script
+     * @param script The script causing the exception
+     * @param reproducer Reproducer which should be used to reproduce the test case.
+     */
+    private void recordException(Throwable e, String script, Consumer<String> reproducer) {
+        for (var ex : exceptions) {
+            if (FuzzerUtils.isExceptionFromSameCause(ex, e)) return;
+        }
+        exceptions.add(e);
+        System.out.println("========== Stack ==========");
+        e.printStackTrace(System.out);
+        System.out.println("========== Code ===========");
+        System.out.println(script);
+        System.out.println("========= Reduced =========");
+        System.out.println(Reducer.reduce(script, e, reproducer));
+        System.out.println("===========================");
+        System.out.flush();
+    }
+
+    /**
+     * Check that two graphs result in the same output when supplied with a value
+     * @param stop1 Stop node of the first graph
+     * @param stop2 Stop node of the second graph
+     * @param in The input value to both graphs to test for an equal output
+     */
+    private static void checkGraphs(StopNode stop1, StopNode stop2, long in) {
+        var e1 = GraphEvaluator.evaluateWithResult(stop1, in, EVAL_TIMEOUT);
+        var e2 = GraphEvaluator.evaluateWithResult(stop2, in, EVAL_TIMEOUT);
+        if (e1.type() == GraphEvaluator.ResultType.TIMEOUT || e2.type() == GraphEvaluator.ResultType.TIMEOUT) return;
+        if (e1.type() != e2.type())
+            throw new RuntimeException("Different calculations types " + e1.type() + " vs " + e2.type());
+        if (e1.value() != e2.value())
+            throw new RuntimeException("Different calculations values " + e1.value() + " vs " + e2.value());
+    }
+
+    /**
+     * Run checks for script. Compile the script with peeps enabled and disabled.
+     * Check that exceptions raised in the parser by both methods are the same and only happens if the script may be invalid.
+     * If the script was successfully parsed check that both version behave the same.
+     * @param script The script to test
+     * @param valid If the script is definitely valid. If not some exceptions may be suppressed.
+     */
+    private static void runCheck(String script, boolean valid) {
+        StopNode stop1;
+        try {
+            stop1 = FuzzerUtils.parse(script, false);
+        } catch (RuntimeException e1) {
+            try {
+                FuzzerUtils.parse(script, true);
+            } catch (RuntimeException e2) {
+                if (FuzzerUtils.isExceptionFromSameCause(e1, e2)) {
+                    if (!valid || e1.getClass() == RuntimeException.class) return;
+                } else {
+                    e1.addSuppressed(e2);
+                }
+            }
+            throw e1;
+        }
+        var stop2 = FuzzerUtils.parse(script, true);
+        checkGraphs(stop1, stop2, 0);
+        checkGraphs(stop1, stop2, 1);
+        checkGraphs(stop1, stop2, 10);
+    }
+
+    /**
+     * Check that the script does not result in exceptions.
+     * @param script The script to test.
+     * @param valid If the script is valid or if it might contain syntax errors.
+     */
+    private void check(String script, boolean valid) {
+        try {
+            runCheck(script, valid);
+        } catch (Throwable e) {
+            recordException(e, script, s->runCheck(s, valid));
+        }
+    }
+
+    /**
+     * Run one test with the given seed.
+     * @param seed The seed to use for generating this test case
+     */
+    public void fuzzPeeps(long seed) {
+        var rand = new Random(seed);
+        var sb = new StringBuilder();
+        var valid = new ScriptGenerator(rand, sb, false).genProgram();
+        check(sb.toString(), valid);
+    }
+
+    /**
+     * Check that no exceptions happened.
+     * @return true if no exception happened
+     */
+    public boolean noExceptions() {
+        return exceptions.isEmpty();
+    }
+}
diff --git a/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/FuzzerUtils.java b/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/FuzzerUtils.java
index ad499836..37a57e11 100644
--- a/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/FuzzerUtils.java
+++ b/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/FuzzerUtils.java
@@ -1,58 +1,58 @@
-package com.seaofnodes.simple.fuzzer;
-
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.node.Node;
-import com.seaofnodes.simple.node.StopNode;
-
-/**
- * Some utilities for the fuzzer.
- */
-class FuzzerUtils {
-
-    /**
-     * Check that eiter one of the objects is null or that both are equal.
-     */
-    private static boolean equalOrNull(Object a, Object b) {
-        if (a == null || b == null) return true;
-        return a.equals(b);
-    }
-
-    /**
-     * Check if both stack traces have the same first entry. Empty stack traces can happen with NPE optimization
-     * and allow the other to be any stack trace.
-     */
-    private static boolean sameStackTraceOrigin(StackTraceElement[] a, StackTraceElement[] b) {
-        if (a == null || a.length == 0 || b == null || b.length == 0) return true; // One or both stack traces are missing.
-        return a[0].equals(b[0]);
-    }
-
-    /**
-     * Checks if two exceptions are caused by the same problem.
-     */
-    public static boolean isExceptionFromSameCause(Throwable a, Throwable b) {
-        if (a == null || b == null) return a == b; // Handle the null case
-        if (a.getClass() != b.getClass()) return false; // Different classes
-        if (!equalOrNull(a.getMessage(), b.getMessage())) return false; // Different messages. Null is allowed as wildcard
-        var s1 = a.getStackTrace();
-        var s2 = b.getStackTrace();
-        if (!sameStackTraceOrigin(s1, s2)) return false; // Different stack trace origins
-        if (!isExceptionFromSameCause(a.getCause(), b.getCause())) return false; // Different causes
-        var o1 = a.getSuppressed();
-        var o2 = b.getSuppressed();
-        if (o1 == null || o2 == null || o1.length != o2.length) return o1 == o2; // Different suppression
-        for (int i=0; i<o1.length; i++) {
-            if (!isExceptionFromSameCause(o1[i], o2[i])) return false; // Different suppression
-        }
-        return true;
-    }
-
-    /**
-     * Parse script with peepholes enabled or disabled
-     */
-    public static StopNode parse(String script, boolean runPeeps) {
-        var parser = new Parser(script);
-        Node._disablePeephole = !runPeeps;
-        return parser.parse();
-    }
-
-}
+package com.seaofnodes.simple.fuzzer;
+
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.node.Node;
+import com.seaofnodes.simple.node.StopNode;
+
+/**
+ * Some utilities for the fuzzer.
+ */
+class FuzzerUtils {
+
+    /**
+     * Check that eiter one of the objects is null or that both are equal.
+     */
+    private static boolean equalOrNull(Object a, Object b) {
+        if (a == null || b == null) return true;
+        return a.equals(b);
+    }
+
+    /**
+     * Check if both stack traces have the same first entry. Empty stack traces can happen with NPE optimization
+     * and allow the other to be any stack trace.
+     */
+    private static boolean sameStackTraceOrigin(StackTraceElement[] a, StackTraceElement[] b) {
+        if (a == null || a.length == 0 || b == null || b.length == 0) return true; // One or both stack traces are missing.
+        return a[0].equals(b[0]);
+    }
+
+    /**
+     * Checks if two exceptions are caused by the same problem.
+     */
+    public static boolean isExceptionFromSameCause(Throwable a, Throwable b) {
+        if (a == null || b == null) return a == b; // Handle the null case
+        if (a.getClass() != b.getClass()) return false; // Different classes
+        if (!equalOrNull(a.getMessage(), b.getMessage())) return false; // Different messages. Null is allowed as wildcard
+        var s1 = a.getStackTrace();
+        var s2 = b.getStackTrace();
+        if (!sameStackTraceOrigin(s1, s2)) return false; // Different stack trace origins
+        if (!isExceptionFromSameCause(a.getCause(), b.getCause())) return false; // Different causes
+        var o1 = a.getSuppressed();
+        var o2 = b.getSuppressed();
+        if (o1 == null || o2 == null || o1.length != o2.length) return o1 == o2; // Different suppression
+        for (int i=0; i<o1.length; i++) {
+            if (!isExceptionFromSameCause(o1[i], o2[i])) return false; // Different suppression
+        }
+        return true;
+    }
+
+    /**
+     * Parse script with peepholes enabled or disabled
+     */
+    public static StopNode parse(String script, boolean runPeeps) {
+        var parser = new Parser(script);
+        Node._disablePeephole = !runPeeps;
+        return parser.parse();
+    }
+
+}
diff --git a/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/Reducer.java b/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/Reducer.java
index 355793bf..b7fc18ec 100644
--- a/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/Reducer.java
+++ b/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/Reducer.java
@@ -1,144 +1,144 @@
-package com.seaofnodes.simple.fuzzer;
-
-import java.util.function.Consumer;
-import java.util.function.Predicate;
-import java.util.regex.Pattern;
-
-/**
- * This class is used to reduce test cases created by the fuzzer.
- * It applies rewrite rules to the test case and checks that the
- * test still produces the same exception.
- * This is done in a fixpoint iteration until every rewrite produces
- * no or a different exception.
- */
-public class Reducer {
-
-    /**
-     * Holder for the rewrite rules
-     */
-    private record Replace(Pattern p, String r) {}
-
-    /**
-     * List of rewrite rules.
-     */
-    private static final Replace[] REPLACEMENTS = {
-            new Replace(Pattern.compile("(?<=[+\\-*/<>=(])--"), ""),
-            new Replace(Pattern.compile("\\b--"), "+"),
-            new Replace(Pattern.compile("\\b\\+-"), "-"),
-            new Replace(Pattern.compile("\\bfalse\\b"), "0"),
-            new Replace(Pattern.compile("\\btrue\\b"), "1"),
-            new Replace(Pattern.compile("-"), ""),
-            new Replace(Pattern.compile("(?<![+\\-*/<>=])(?:-|\\*|/|>=|<=|>|<|!=|==)(?![+\\-*/<>=])"), "+"),
-            new Replace(Pattern.compile("\\{(?:[^{}]|\\{})+}"), "{}"),
-            new Replace(Pattern.compile("\\{((?:[^{}]|\\{})+)}"), "$1"),
-            new Replace(Pattern.compile("\\(([^()]+)\\)"), "$1"),
-            new Replace(Pattern.compile("\\b\\w+\\b"), "1"),
-            new Replace(Pattern.compile("\\b\\w+\\b"), "0"),
-            new Replace(Pattern.compile("\\d+\\+"), ""),
-            new Replace(Pattern.compile("\\+\\d+"), ""),
-            new Replace(Pattern.compile("(?<=\\n|^)[^\\n]*(?=\\n|$)"), "\n"),
-            new Replace(Pattern.compile("\\n+"), "\n"),
-            new Replace(Pattern.compile("^\\n+|\\n+$"), ""),
-            new Replace(Pattern.compile("else *"), ""),
-            new Replace(Pattern.compile("\\bif\\([^()]+\\) *"), ""),
-            new Replace(Pattern.compile("\\bwhile\\([^()]+\\) *"), ""),
-    };
-
-    /**
-     * Predicate to test if the reduced script generates the same error.
-     */
-    private final Predicate<String> tester;
-
-    /**
-     * Create a reducer with a test function.
-     * @param tester Test function which returns true when the same issue is found in the script.
-     */
-    private Reducer(Predicate<String> tester) {
-        this.tester = tester;
-    }
-
-    /**
-     * Rewrites the script with one rewrite rule.
-     */
-    private String doReplacement(String script, Pattern pattern, String with) {
-        var matcher = pattern.matcher(script);
-        var sb = new StringBuilder();
-        int last = 0;
-        while (matcher.find()) {
-            var pos = sb.length();
-            matcher.appendReplacement(sb, with);
-            var tail = sb.length();
-            matcher.appendTail(sb);
-            if (tester.test(sb.toString())) {
-                sb.setLength(tail);
-            } else {
-                sb.setLength(pos);
-                sb.append(script, last, matcher.end());
-            }
-            last = matcher.end();
-        }
-        matcher.appendTail(sb);
-        return sb.toString();
-    }
-
-    /**
-     * Clean up variable names from the random ones generated by the fuzzer.
-     */
-    private String cleanVariables(String script) {
-        var matcher = Pattern.compile("\\bint ([0-9a-zA-Z_]+)").matcher(script);
-        int num = 0;
-        while (matcher.find()) {
-            var var = matcher.group(1);
-            if (var.matches("v\\d+")) continue;
-            while (script.contains("v"+num)) num++;
-            var n = script.replaceAll("\\b"+var+"\\b", "v" + num);
-            if (tester.test(n)) {
-                script = n;
-            }
-        }
-        return script;
-    }
-
-    /**
-     * Run all rewrite rules once.
-     */
-    private String doAllReplacements(String script) {
-        for (var replace: REPLACEMENTS) {
-            script = doReplacement(script, replace.p, replace.r);
-        }
-        return script;
-    }
-
-    /**
-     * Reduce the script to a minimal version which produces the same problem with a test function.
-     * @param tester Test function which returns true when the same issue is found in the script.
-     */
-    public static String reduce(String script, Predicate<String> tester) {
-        var reducer = new Reducer(tester);
-        String old;
-        do {
-            old = script;
-            script = reducer.doAllReplacements(script);
-            script = reducer.cleanVariables(script);
-        } while (!script.equals(old));
-        return script;
-    }
-
-    /**
-     * Reduce the script to a minimal version which produces the same problem with a reproducer.
-     * @param ex The exception originally caused by the script
-     * @param reproducer Test function which throws an exception which will be checked against ex.
-     */
-    public static String reduce(String script, Throwable ex, Consumer<String> reproducer) {
-        return reduce(script, s->{
-            Throwable nex = null;
-            try {
-                reproducer.accept(s);
-            } catch (Throwable e) {
-                nex = e;
-            }
-            return FuzzerUtils.isExceptionFromSameCause(nex, ex);
-        });
-    }
-
-}
+package com.seaofnodes.simple.fuzzer;
+
+import java.util.function.Consumer;
+import java.util.function.Predicate;
+import java.util.regex.Pattern;
+
+/**
+ * This class is used to reduce test cases created by the fuzzer.
+ * It applies rewrite rules to the test case and checks that the
+ * test still produces the same exception.
+ * This is done in a fixpoint iteration until every rewrite produces
+ * no or a different exception.
+ */
+public class Reducer {
+
+    /**
+     * Holder for the rewrite rules
+     */
+    private record Replace(Pattern p, String r) {}
+
+    /**
+     * List of rewrite rules.
+     */
+    private static final Replace[] REPLACEMENTS = {
+            new Replace(Pattern.compile("(?<=[+\\-*/<>=(])--"), ""),
+            new Replace(Pattern.compile("\\b--"), "+"),
+            new Replace(Pattern.compile("\\b\\+-"), "-"),
+            new Replace(Pattern.compile("\\bfalse\\b"), "0"),
+            new Replace(Pattern.compile("\\btrue\\b"), "1"),
+            new Replace(Pattern.compile("-"), ""),
+            new Replace(Pattern.compile("(?<![+\\-*/<>=])(?:-|\\*|/|>=|<=|>|<|!=|==)(?![+\\-*/<>=])"), "+"),
+            new Replace(Pattern.compile("\\{(?:[^{}]|\\{})+}"), "{}"),
+            new Replace(Pattern.compile("\\{((?:[^{}]|\\{})+)}"), "$1"),
+            new Replace(Pattern.compile("\\(([^()]+)\\)"), "$1"),
+            new Replace(Pattern.compile("\\b\\w+\\b"), "1"),
+            new Replace(Pattern.compile("\\b\\w+\\b"), "0"),
+            new Replace(Pattern.compile("\\d+\\+"), ""),
+            new Replace(Pattern.compile("\\+\\d+"), ""),
+            new Replace(Pattern.compile("(?<=\\n|^)[^\\n]*(?=\\n|$)"), "\n"),
+            new Replace(Pattern.compile("\\n+"), "\n"),
+            new Replace(Pattern.compile("^\\n+|\\n+$"), ""),
+            new Replace(Pattern.compile("else *"), ""),
+            new Replace(Pattern.compile("\\bif\\([^()]+\\) *"), ""),
+            new Replace(Pattern.compile("\\bwhile\\([^()]+\\) *"), ""),
+    };
+
+    /**
+     * Predicate to test if the reduced script generates the same error.
+     */
+    private final Predicate<String> tester;
+
+    /**
+     * Create a reducer with a test function.
+     * @param tester Test function which returns true when the same issue is found in the script.
+     */
+    private Reducer(Predicate<String> tester) {
+        this.tester = tester;
+    }
+
+    /**
+     * Rewrites the script with one rewrite rule.
+     */
+    private String doReplacement(String script, Pattern pattern, String with) {
+        var matcher = pattern.matcher(script);
+        var sb = new StringBuilder();
+        int last = 0;
+        while (matcher.find()) {
+            var pos = sb.length();
+            matcher.appendReplacement(sb, with);
+            var tail = sb.length();
+            matcher.appendTail(sb);
+            if (tester.test(sb.toString())) {
+                sb.setLength(tail);
+            } else {
+                sb.setLength(pos);
+                sb.append(script, last, matcher.end());
+            }
+            last = matcher.end();
+        }
+        matcher.appendTail(sb);
+        return sb.toString();
+    }
+
+    /**
+     * Clean up variable names from the random ones generated by the fuzzer.
+     */
+    private String cleanVariables(String script) {
+        var matcher = Pattern.compile("\\bint ([0-9a-zA-Z_]+)").matcher(script);
+        int num = 0;
+        while (matcher.find()) {
+            var var = matcher.group(1);
+            if (var.matches("v\\d+")) continue;
+            while (script.contains("v"+num)) num++;
+            var n = script.replaceAll("\\b"+var+"\\b", "v" + num);
+            if (tester.test(n)) {
+                script = n;
+            }
+        }
+        return script;
+    }
+
+    /**
+     * Run all rewrite rules once.
+     */
+    private String doAllReplacements(String script) {
+        for (var replace: REPLACEMENTS) {
+            script = doReplacement(script, replace.p, replace.r);
+        }
+        return script;
+    }
+
+    /**
+     * Reduce the script to a minimal version which produces the same problem with a test function.
+     * @param tester Test function which returns true when the same issue is found in the script.
+     */
+    public static String reduce(String script, Predicate<String> tester) {
+        var reducer = new Reducer(tester);
+        String old;
+        do {
+            old = script;
+            script = reducer.doAllReplacements(script);
+            script = reducer.cleanVariables(script);
+        } while (!script.equals(old));
+        return script;
+    }
+
+    /**
+     * Reduce the script to a minimal version which produces the same problem with a reproducer.
+     * @param ex The exception originally caused by the script
+     * @param reproducer Test function which throws an exception which will be checked against ex.
+     */
+    public static String reduce(String script, Throwable ex, Consumer<String> reproducer) {
+        return reduce(script, s->{
+            Throwable nex = null;
+            try {
+                reproducer.accept(s);
+            } catch (Throwable e) {
+                nex = e;
+            }
+            return FuzzerUtils.isExceptionFromSameCause(nex, ex);
+        });
+    }
+
+}
diff --git a/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java b/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java
index 9df3dfcc..148c2319 100644
--- a/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java
+++ b/chapter08/src/test/java/com/seaofnodes/simple/fuzzer/ScriptGenerator.java
@@ -1,462 +1,462 @@
-package com.seaofnodes.simple.fuzzer;
-
-import com.seaofnodes.simple.Parser;
-import com.seaofnodes.simple.node.ScopeNode;
-
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.Random;
-
-/**
- * Generate a pseudo random script.
- * This generator will generate the same script for two random number generators initialized with the same seed.
- * To generate valid code it implements the parser but instead of parsing it emits the statements and expressions.
- * It is guaranteed to terminate.
- */
-public class ScriptGenerator {
-
-    /**
-     * Get the list of keywords from the parser.
-     */
-    @SuppressWarnings("unchecked")
-    private static HashSet<String> getKeywords() {
-        try {
-            var field = Parser.class.getDeclaredField("KEYWORDS");
-            field.setAccessible(true);
-            return (HashSet<String>) field.get(new Parser(""));
-        } catch (Throwable e) {
-            throw new ExceptionInInitializerError(e);
-        }
-    }
-
-    /**
-     * Number of spaces per indentation
-     */
-    private static final int INDENTATION = 4;
-    /**
-     * Valid characters for identifiers. The last 10 are not valid for the first character.
-     */
-    private static final String VAR_CHARS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_0123456789";
-    /**
-     * List of keywords not valid for identifiers.
-     */
-    private static final HashSet<String> KEYWORDS = getKeywords();
-
-    /**
-     * Flag for a statement that it does not pass on control flow to the next statement.
-     */
-    private static final int FLAG_STOP = 0x01;
-    /**
-     * Flag for a statement that it contains a final if statement without an else branch.
-     */
-    private static final int FLAG_IF_WITHOUT_ELSE = 0x02;
-    /**
-     * Binary operators.
-     */
-    private static final String[] BINARY_OP = {"==", "!=", "<", "<=", ">", ">=", "+", "-", "*", "/"};
-    /**
-     * Unary operators.
-     */
-    private static final String[] UNARY_OP = {"-"};
-
-
-    /**
-     * The random number generator used for random decisions.
-     */
-    private final Random random;
-    /**
-     * Indentation depth.
-     */
-    private int indentation = 0;
-    /**
-     * Output string builder
-     */
-    private final StringBuilder sb;
-    /**
-     * Number of nested loops
-     */
-    private int loopDepth = 0;
-    /**
-     * Current scope start in the variables list.
-     */
-    private int currScopeStart = 0;
-    /**
-     * The depth of blocks allowed.
-     */
-    private int depth = 7;
-    /**
-     * The depth of expressions allowed.
-     */
-    private int exprDepth = 3;
-    /**
-     * Current variables in scope.
-     */
-    private final ArrayList<String> variables = new ArrayList<>();
-    /**
-     * If this needs to generate valid scripts or is also allowed to generate invalid ones.
-     */
-    private final boolean generateValid;
-    /**
-     * If this script might be invalid.
-     */
-    private boolean maybeInvalid = false;
-
-    /**
-     *
-     * @param random the random number generator.
-     * @param sb the script will be written to this string builder.
-     * @param generateValid if the script should be guaranteed valid or if it is allowed to contain bugs.
-     */
-    public ScriptGenerator(Random random, StringBuilder sb, boolean generateValid) {
-        this.random = random;
-        this.sb = sb;
-        this.generateValid = generateValid;
-    }
-
-    /**
-     * Random number with log distribution
-     * @param max The maximum value
-     * @return A random number in the range [0, max) with higher numbers being more uncommon.
-     */
-    private int randLog(int max) {
-        max--;
-        int n = 1<<max;
-        var num = random.nextInt(n);
-        for (int i=max-1; i>=0; i--) {
-            if ((num & (1<<i))!=0) return max-i-1;
-        }
-        return max;
-    }
-
-    /**
-     * Helper function to print indentation.
-     * @return sb for chaining
-     */
-    private StringBuilder printIndentation() {
-        return sb.repeat(' ', indentation);
-    }
-
-    /**
-     * Generate a random name for variables. This might be invalid when it is a keyword.
-     * @return The random name generated
-     */
-    private StringBuilder getRandomName() {
-        int len = random.nextInt(10) + 1;
-        StringBuilder sb = new StringBuilder(len);
-        sb.append(VAR_CHARS.charAt(random.nextInt(VAR_CHARS.length()-10)));
-        for (int i=1; i<len; i++)
-            sb.append(VAR_CHARS.charAt(random.nextInt(VAR_CHARS.length())));
-        return sb;
-    }
-
-    /**
-     * Generate a variable name. This might be new random name or a name from an outer scope.
-     * If the program is allowed to be invalid this can return keywords and already used variable names in the current scope.
-     * @return The variable name.
-     */
-    private String getVarName() {
-        if (currScopeStart > 0 && random.nextInt(10) > 7) {
-            // Use a variable outside the current scope.
-            var v = variables.get(random.nextInt(currScopeStart));
-            if (variables.lastIndexOf(v) < currScopeStart) return v;
-            if (!generateValid) {
-                maybeInvalid = true;
-                return v;
-            }
-        }
-        // Generate a new random variable name
-        StringBuilder sb = getRandomName();
-        var v = sb.toString();
-        if (!generateValid && (KEYWORDS.contains(v) || variables.lastIndexOf(v) >= currScopeStart)) {
-            maybeInvalid = true;
-            return v;
-        }
-        while (KEYWORDS.contains(v) || variables.lastIndexOf(v) >= currScopeStart) {
-            sb.append(VAR_CHARS.charAt(random.nextInt(VAR_CHARS.length())));
-            v = sb.toString();
-        }
-        return v;
-    }
-
-
-
-    /**
-     * Generates a program and writes it into the string builder supplied in the constructor.
-     * @return If the program is allowed to be invalid returns if something potentially invalid was generated.
-     */
-    public boolean genProgram() {
-        this.maybeInvalid = false;
-        variables.add(ScopeNode.ARG0);
-        currScopeStart = variables.size();
-        if ((genStatements() & FLAG_STOP) == 0) {
-            if (generateValid || random.nextInt(10)<7) {
-                genReturn();
-            } else {
-                this.maybeInvalid = true;
-            }
-        }
-        return !this.maybeInvalid;
-    }
-
-    /**
-     * Generate a list of statements.
-     * @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the last statement generated
-     */
-    public int genStatements() {
-        var num = random.nextInt(10);
-        for (int i=0; i<num; i++) {
-            printIndentation();
-            var stop = genStatement();
-            sb.append("\n");
-            if ((stop & FLAG_STOP) != 0) return stop;
-        }
-        return 0;
-    }
-
-    /**
-     * Generate a single statement
-     * @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the generated statement
-     */
-    public int genStatement() {
-        return switch (random.nextInt(10)) {
-            case 1 -> genBlock();
-            case 2 -> genIf();
-            case 3 -> genWhile();
-            case 4, 5 -> genDecl();
-            case 6, 7, 8 -> genAssignment();
-            default -> genExit();
-        };
-    }
-
-    /**
-     * Generate a statement for if, else and while blocks.
-     * This is special since it disallows declarations and prefers to generate blocks.
-     * @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the generated statement
-     */
-    public int genStatementBlock() {
-        indentation += INDENTATION;
-        int res;
-        if (depth == 0) {
-            res = random.nextBoolean() ? genAssignment() : genExit();
-        } else {
-            depth--;
-            res = switch (random.nextInt(10)) {
-                case 1, 2, 3, 4, 5 -> {
-                    depth++;
-                    indentation -= INDENTATION;
-                    var ret = genBlock();
-                    indentation += INDENTATION;
-                    depth--;
-                    yield ret;
-                }
-                case 6 -> genIf();
-                case 7 -> genWhile();
-                case 8 -> genAssignment();
-                default -> genExit();
-            };
-            depth++;
-        }
-        indentation -= INDENTATION;
-        return res;
-    }
-
-    /**
-     * Generate an exit. This can be return or break and continue when in a loop.
-     * @return FLAG_STOP
-     */
-    public int genExit() {
-        if (loopDepth == 0 && generateValid) return genReturn();
-        return switch (random.nextInt(7)) {
-            case 0,1,2 -> {
-                if (loopDepth == 0) maybeInvalid = true;
-                sb.append("continue;");
-                yield FLAG_STOP;
-            }
-            case 3,4,5 -> {
-                if (loopDepth == 0) maybeInvalid = true;
-                sb.append("break;");
-                yield FLAG_STOP;
-            }
-            default -> genReturn();
-        };
-    }
-
-    /**
-     * Generate a block statement. After a certain depth only empty blocks are generated to ensure termination of the generator.
-     * @return flag FLAG_STOP for the generated statement
-     */
-    public int genBlock() {
-        if (depth == 0) {
-            sb.append("{}");
-            return 0;
-        }
-        depth--;
-        int oldCSS = currScopeStart;
-        currScopeStart = variables.size();
-        sb.append("{\n");
-        indentation += INDENTATION;
-        var stop = genStatements();
-        indentation -= INDENTATION;
-        printIndentation().append("}");
-        while (variables.size() > currScopeStart)
-            variables.removeLast();
-        currScopeStart = oldCSS;
-        depth++;
-        return stop & ~FLAG_IF_WITHOUT_ELSE;
-    }
-
-    /**
-     * Generate an if statement with an optional else block.
-     * @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the generated statement
-     */
-    public int genIf() {
-        sb.append("if(");
-        genExpression();
-        sb.append(") ");
-        var stop = genStatementBlock();
-        if ((stop & FLAG_IF_WITHOUT_ELSE) == 0 && random.nextInt(10) > 3) {
-            sb.append("\n");
-            printIndentation().append("else ");
-            stop &= genStatementBlock();
-        } else {
-            stop = FLAG_IF_WITHOUT_ELSE;
-        }
-        return stop;
-    }
-
-    /**
-     * Generate a while loop.
-     * @return 0
-     */
-    public int genWhile() {
-        sb.append("while(");
-        genExpression();
-        sb.append(") ");
-        loopDepth++;
-        genStatementBlock();
-        loopDepth--;
-        return 0;
-    }
-
-    /**
-     * Generate a declaration statement.
-     * @return 0
-     */
-    public int genDecl() {
-        String name = getVarName();
-        sb.append("int ").append(name).append("=");
-        genExpression();
-        sb.append(";");
-        variables.add(name);
-        return 0;
-    }
-
-    /**
-     * Generate an assignment statement.
-     * @return 0
-     */
-    public int genAssignment() {
-        if (variables.isEmpty()) return genDecl();
-        genVariable();
-        sb.append("=");
-        genExpression();
-        sb.append(";");
-        return 0;
-    }
-
-    /**
-     * Generate a return statement.
-     * @return FLAG_STOP
-     */
-    public int genReturn() {
-        sb.append("return ");
-        genExpression();
-        sb.append(";");
-        return FLAG_STOP;
-    }
-
-
-    /**
-     * Generate a binary expression.
-     * This method does not care about operator precedence.
-     */
-    public void genExpression() {
-        var num = randLog(10);
-        while(num-->0) {
-            genUnary();
-            sb.append(BINARY_OP[random.nextInt(BINARY_OP.length)]);
-        }
-        genUnary();
-    }
-
-    /**
-     * Generate a unary expression.
-     */
-    public void genUnary() {
-        var num = randLog(6);
-        while(num-->0) {
-            sb.append(UNARY_OP[random.nextInt(UNARY_OP.length)]);
-        }
-        genPrimary();
-    }
-
-    /**
-     * Generate a primary expression.
-     */
-    public void genPrimary() {
-        switch (random.nextInt(10)) {
-            case 0:
-                sb.append("true");
-                break;
-            case 1:
-                sb.append("false");
-                break;
-            case 2:
-                if (exprDepth == 0) {
-                    // Ensure termination of the generator.
-                    if (random.nextBoolean()) {
-                        genNumber();
-                    } else {
-                        genVariable();
-                    }
-                } else {
-                    sb.append("(");
-                    exprDepth--;
-                    genExpression();
-                    exprDepth++;
-                    sb.append(")");
-                }
-                break;
-            case 3, 4, 5, 6:
-                genNumber();
-                break;
-            default:
-                genVariable();
-        }
-    }
-
-    /**
-     * Generate a number.
-     */
-    public void genNumber() {
-        sb.append(random.nextInt(100));
-    }
-
-    /**
-     * Generate a variable. If there are none generate a number instead.
-     * If the program is allowed to be invalid a random name can be generated in some cases.
-     */
-    public void genVariable() {
-        if (!generateValid && random.nextInt(100)>97) {
-            sb.append(getRandomName());
-            maybeInvalid = true;
-            return;
-        }
-        if (variables.isEmpty()) {
-            genNumber();
-        } else {
-            sb.append(variables.get(random.nextInt(variables.size())));
-        }
-    }
-
-}
+package com.seaofnodes.simple.fuzzer;
+
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.node.ScopeNode;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Random;
+
+/**
+ * Generate a pseudo random script.
+ * This generator will generate the same script for two random number generators initialized with the same seed.
+ * To generate valid code it implements the parser but instead of parsing it emits the statements and expressions.
+ * It is guaranteed to terminate.
+ */
+public class ScriptGenerator {
+
+    /**
+     * Get the list of keywords from the parser.
+     */
+    @SuppressWarnings("unchecked")
+    private static HashSet<String> getKeywords() {
+        try {
+            var field = Parser.class.getDeclaredField("KEYWORDS");
+            field.setAccessible(true);
+            return (HashSet<String>) field.get(new Parser(""));
+        } catch (Throwable e) {
+            throw new ExceptionInInitializerError(e);
+        }
+    }
+
+    /**
+     * Number of spaces per indentation
+     */
+    private static final int INDENTATION = 4;
+    /**
+     * Valid characters for identifiers. The last 10 are not valid for the first character.
+     */
+    private static final String VAR_CHARS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_0123456789";
+    /**
+     * List of keywords not valid for identifiers.
+     */
+    private static final HashSet<String> KEYWORDS = getKeywords();
+
+    /**
+     * Flag for a statement that it does not pass on control flow to the next statement.
+     */
+    private static final int FLAG_STOP = 0x01;
+    /**
+     * Flag for a statement that it contains a final if statement without an else branch.
+     */
+    private static final int FLAG_IF_WITHOUT_ELSE = 0x02;
+    /**
+     * Binary operators.
+     */
+    private static final String[] BINARY_OP = {"==", "!=", "<", "<=", ">", ">=", "+", "-", "*", "/"};
+    /**
+     * Unary operators.
+     */
+    private static final String[] UNARY_OP = {"-"};
+
+
+    /**
+     * The random number generator used for random decisions.
+     */
+    private final Random random;
+    /**
+     * Indentation depth.
+     */
+    private int indentation = 0;
+    /**
+     * Output string builder
+     */
+    private final StringBuilder sb;
+    /**
+     * Number of nested loops
+     */
+    private int loopDepth = 0;
+    /**
+     * Current scope start in the variables list.
+     */
+    private int currScopeStart = 0;
+    /**
+     * The depth of blocks allowed.
+     */
+    private int depth = 7;
+    /**
+     * The depth of expressions allowed.
+     */
+    private int exprDepth = 3;
+    /**
+     * Current variables in scope.
+     */
+    private final ArrayList<String> variables = new ArrayList<>();
+    /**
+     * If this needs to generate valid scripts or is also allowed to generate invalid ones.
+     */
+    private final boolean generateValid;
+    /**
+     * If this script might be invalid.
+     */
+    private boolean maybeInvalid = false;
+
+    /**
+     *
+     * @param random the random number generator.
+     * @param sb the script will be written to this string builder.
+     * @param generateValid if the script should be guaranteed valid or if it is allowed to contain bugs.
+     */
+    public ScriptGenerator(Random random, StringBuilder sb, boolean generateValid) {
+        this.random = random;
+        this.sb = sb;
+        this.generateValid = generateValid;
+    }
+
+    /**
+     * Random number with log distribution
+     * @param max The maximum value
+     * @return A random number in the range [0, max) with higher numbers being more uncommon.
+     */
+    private int randLog(int max) {
+        max--;
+        int n = 1<<max;
+        var num = random.nextInt(n);
+        for (int i=max-1; i>=0; i--) {
+            if ((num & (1<<i))!=0) return max-i-1;
+        }
+        return max;
+    }
+
+    /**
+     * Helper function to print indentation.
+     * @return sb for chaining
+     */
+    private StringBuilder printIndentation() {
+        return sb.repeat(' ', indentation);
+    }
+
+    /**
+     * Generate a random name for variables. This might be invalid when it is a keyword.
+     * @return The random name generated
+     */
+    private StringBuilder getRandomName() {
+        int len = random.nextInt(10) + 1;
+        StringBuilder sb = new StringBuilder(len);
+        sb.append(VAR_CHARS.charAt(random.nextInt(VAR_CHARS.length()-10)));
+        for (int i=1; i<len; i++)
+            sb.append(VAR_CHARS.charAt(random.nextInt(VAR_CHARS.length())));
+        return sb;
+    }
+
+    /**
+     * Generate a variable name. This might be new random name or a name from an outer scope.
+     * If the program is allowed to be invalid this can return keywords and already used variable names in the current scope.
+     * @return The variable name.
+     */
+    private String getVarName() {
+        if (currScopeStart > 0 && random.nextInt(10) > 7) {
+            // Use a variable outside the current scope.
+            var v = variables.get(random.nextInt(currScopeStart));
+            if (variables.lastIndexOf(v) < currScopeStart) return v;
+            if (!generateValid) {
+                maybeInvalid = true;
+                return v;
+            }
+        }
+        // Generate a new random variable name
+        StringBuilder sb = getRandomName();
+        var v = sb.toString();
+        if (!generateValid && (KEYWORDS.contains(v) || variables.lastIndexOf(v) >= currScopeStart)) {
+            maybeInvalid = true;
+            return v;
+        }
+        while (KEYWORDS.contains(v) || variables.lastIndexOf(v) >= currScopeStart) {
+            sb.append(VAR_CHARS.charAt(random.nextInt(VAR_CHARS.length())));
+            v = sb.toString();
+        }
+        return v;
+    }
+
+
+
+    /**
+     * Generates a program and writes it into the string builder supplied in the constructor.
+     * @return If the program is allowed to be invalid returns if something potentially invalid was generated.
+     */
+    public boolean genProgram() {
+        this.maybeInvalid = false;
+        variables.add(ScopeNode.ARG0);
+        currScopeStart = variables.size();
+        if ((genStatements() & FLAG_STOP) == 0) {
+            if (generateValid || random.nextInt(10)<7) {
+                genReturn();
+            } else {
+                this.maybeInvalid = true;
+            }
+        }
+        return !this.maybeInvalid;
+    }
+
+    /**
+     * Generate a list of statements.
+     * @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the last statement generated
+     */
+    public int genStatements() {
+        var num = random.nextInt(10);
+        for (int i=0; i<num; i++) {
+            printIndentation();
+            var stop = genStatement();
+            sb.append("\n");
+            if ((stop & FLAG_STOP) != 0) return stop;
+        }
+        return 0;
+    }
+
+    /**
+     * Generate a single statement
+     * @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the generated statement
+     */
+    public int genStatement() {
+        return switch (random.nextInt(10)) {
+            case 1 -> genBlock();
+            case 2 -> genIf();
+            case 3 -> genWhile();
+            case 4, 5 -> genDecl();
+            case 6, 7, 8 -> genAssignment();
+            default -> genExit();
+        };
+    }
+
+    /**
+     * Generate a statement for if, else and while blocks.
+     * This is special since it disallows declarations and prefers to generate blocks.
+     * @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the generated statement
+     */
+    public int genStatementBlock() {
+        indentation += INDENTATION;
+        int res;
+        if (depth == 0) {
+            res = random.nextBoolean() ? genAssignment() : genExit();
+        } else {
+            depth--;
+            res = switch (random.nextInt(10)) {
+                case 1, 2, 3, 4, 5 -> {
+                    depth++;
+                    indentation -= INDENTATION;
+                    var ret = genBlock();
+                    indentation += INDENTATION;
+                    depth--;
+                    yield ret;
+                }
+                case 6 -> genIf();
+                case 7 -> genWhile();
+                case 8 -> genAssignment();
+                default -> genExit();
+            };
+            depth++;
+        }
+        indentation -= INDENTATION;
+        return res;
+    }
+
+    /**
+     * Generate an exit. This can be return or break and continue when in a loop.
+     * @return FLAG_STOP
+     */
+    public int genExit() {
+        if (loopDepth == 0 && generateValid) return genReturn();
+        return switch (random.nextInt(7)) {
+            case 0,1,2 -> {
+                if (loopDepth == 0) maybeInvalid = true;
+                sb.append("continue;");
+                yield FLAG_STOP;
+            }
+            case 3,4,5 -> {
+                if (loopDepth == 0) maybeInvalid = true;
+                sb.append("break;");
+                yield FLAG_STOP;
+            }
+            default -> genReturn();
+        };
+    }
+
+    /**
+     * Generate a block statement. After a certain depth only empty blocks are generated to ensure termination of the generator.
+     * @return flag FLAG_STOP for the generated statement
+     */
+    public int genBlock() {
+        if (depth == 0) {
+            sb.append("{}");
+            return 0;
+        }
+        depth--;
+        int oldCSS = currScopeStart;
+        currScopeStart = variables.size();
+        sb.append("{\n");
+        indentation += INDENTATION;
+        var stop = genStatements();
+        indentation -= INDENTATION;
+        printIndentation().append("}");
+        while (variables.size() > currScopeStart)
+            variables.removeLast();
+        currScopeStart = oldCSS;
+        depth++;
+        return stop & ~FLAG_IF_WITHOUT_ELSE;
+    }
+
+    /**
+     * Generate an if statement with an optional else block.
+     * @return flags FLAG_STOP and FLAG_IF_WITHOUT_ELSE for the generated statement
+     */
+    public int genIf() {
+        sb.append("if(");
+        genExpression();
+        sb.append(") ");
+        var stop = genStatementBlock();
+        if ((stop & FLAG_IF_WITHOUT_ELSE) == 0 && random.nextInt(10) > 3) {
+            sb.append("\n");
+            printIndentation().append("else ");
+            stop &= genStatementBlock();
+        } else {
+            stop = FLAG_IF_WITHOUT_ELSE;
+        }
+        return stop;
+    }
+
+    /**
+     * Generate a while loop.
+     * @return 0
+     */
+    public int genWhile() {
+        sb.append("while(");
+        genExpression();
+        sb.append(") ");
+        loopDepth++;
+        genStatementBlock();
+        loopDepth--;
+        return 0;
+    }
+
+    /**
+     * Generate a declaration statement.
+     * @return 0
+     */
+    public int genDecl() {
+        String name = getVarName();
+        sb.append("int ").append(name).append("=");
+        genExpression();
+        sb.append(";");
+        variables.add(name);
+        return 0;
+    }
+
+    /**
+     * Generate an assignment statement.
+     * @return 0
+     */
+    public int genAssignment() {
+        if (variables.isEmpty()) return genDecl();
+        genVariable();
+        sb.append("=");
+        genExpression();
+        sb.append(";");
+        return 0;
+    }
+
+    /**
+     * Generate a return statement.
+     * @return FLAG_STOP
+     */
+    public int genReturn() {
+        sb.append("return ");
+        genExpression();
+        sb.append(";");
+        return FLAG_STOP;
+    }
+
+
+    /**
+     * Generate a binary expression.
+     * This method does not care about operator precedence.
+     */
+    public void genExpression() {
+        var num = randLog(10);
+        while(num-->0) {
+            genUnary();
+            sb.append(BINARY_OP[random.nextInt(BINARY_OP.length)]);
+        }
+        genUnary();
+    }
+
+    /**
+     * Generate a unary expression.
+     */
+    public void genUnary() {
+        var num = randLog(6);
+        while(num-->0) {
+            sb.append(UNARY_OP[random.nextInt(UNARY_OP.length)]);
+        }
+        genPrimary();
+    }
+
+    /**
+     * Generate a primary expression.
+     */
+    public void genPrimary() {
+        switch (random.nextInt(10)) {
+            case 0:
+                sb.append("true");
+                break;
+            case 1:
+                sb.append("false");
+                break;
+            case 2:
+                if (exprDepth == 0) {
+                    // Ensure termination of the generator.
+                    if (random.nextBoolean()) {
+                        genNumber();
+                    } else {
+                        genVariable();
+                    }
+                } else {
+                    sb.append("(");
+                    exprDepth--;
+                    genExpression();
+                    exprDepth++;
+                    sb.append(")");
+                }
+                break;
+            case 3, 4, 5, 6:
+                genNumber();
+                break;
+            default:
+                genVariable();
+        }
+    }
+
+    /**
+     * Generate a number.
+     */
+    public void genNumber() {
+        sb.append(random.nextInt(100));
+    }
+
+    /**
+     * Generate a variable. If there are none generate a number instead.
+     * If the program is allowed to be invalid a random name can be generated in some cases.
+     */
+    public void genVariable() {
+        if (!generateValid && random.nextInt(100)>97) {
+            sb.append(getRandomName());
+            maybeInvalid = true;
+            return;
+        }
+        if (variables.isEmpty()) {
+            genNumber();
+        } else {
+            sb.append(variables.get(random.nextInt(variables.size())));
+        }
+    }
+
+}
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