Format whitespace (#86)

* Trim trailing whitespace

* Ensure final new lines

* Convert line endings from CRLF to LF

* Replace tabs with spaces

6 files changed, 854 insertions, 854 deletions

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())));
+        }
+    }
+
+}