Expanded the AST printers to support a target PrintStream, and expanded the @PrintAST annotation to let you supply an optional filename. Useful particularly for IDEs, which don't usually have a viewable console.

Also renamed the printers to just 'Printer', as they are already inner classes of a specifically named type (JavacASTVisitor & co).

src/lombok/core/PrintAST.java

@@ -7,4 +7,6 @@ import java.lang.annotation.Target;
 
 @Target({ElementType.CONSTRUCTOR, ElementType.FIELD, ElementType.LOCAL_VARIABLE, ElementType.METHOD, ElementType.TYPE})
 @Retention(RetentionPolicy.SOURCE)
-public @interface PrintAST {}
+public @interface PrintAST {
+	String outfile() default "";
+}

src/lombok/eclipse/EclipseASTVisitor.java

@@ -1,5 +1,8 @@
 package lombok.eclipse;
 
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.PrintStream;
 import java.lang.reflect.Modifier;
 
 import lombok.eclipse.EclipseAST.Node;
@@ -79,12 +82,26 @@ public interface EclipseASTVisitor {
 	void visitStatement(Node statementNode, Statement statement);
 	void endVisitStatement(Node statementNode, Statement statement);
 	
-	public static class EclipseASTPrinter implements EclipseASTVisitor {
+	public static class Printer implements EclipseASTVisitor {
+		private final PrintStream out;
+		public Printer() {
+			this(System.out);
+		}
+		
+		public Printer(File file) throws FileNotFoundException {
+			this(new PrintStream(file));
+		}
+		
+		public Printer(PrintStream out) {
+			this.out = out;
+		}
+		
 		int indent = 0;
 		private void print(String text, Object... params) {
 			StringBuilder sb = new StringBuilder();
 			for ( int i = 0 ; i < indent ; i++ ) sb.append("  ");
-			System.out.printf(sb.append(text).append('\n').toString(), params);
+			out.printf(sb.append(text).append('\n').toString(), params);
+			out.flush();
 		}
 		
 		private String str(char[] c) {

src/lombok/eclipse/handlers/HandlePrintAST.java

@@ -1,8 +1,13 @@
 package lombok.eclipse.handlers;
 
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.PrintStream;
+
 import org.eclipse.jdt.internal.compiler.ast.Annotation;
 import org.mangosdk.spi.ProviderFor;
 
+import lombok.Lombok;
 import lombok.core.AnnotationValues;
 import lombok.core.PrintAST;
 import lombok.eclipse.EclipseASTVisitor;
@@ -13,7 +18,16 @@ import lombok.eclipse.EclipseAST.Node;
 public class HandlePrintAST implements EclipseAnnotationHandler<PrintAST> {
 	@Override public boolean handle(AnnotationValues<PrintAST> annotation, Annotation ast, Node annotationNode) {
 		if ( !annotationNode.isCompleteParse() ) return false;
-		annotationNode.up().traverse(new EclipseASTVisitor.EclipseASTPrinter());
+		
+		PrintStream stream = System.out;
+		String fileName = annotation.getInstance().outfile();
+		if ( fileName.length() > 0 ) try {
+			stream = new PrintStream(new File(fileName));
+		} catch ( FileNotFoundException e ) {
+			Lombok.sneakyThrow(e);
+		}
+		
+		annotationNode.up().traverse(new EclipseASTVisitor.Printer(stream));
 		return true;
 	}
 }

src/lombok/javac/JavacASTVisitor.java

@@ -1,5 +1,9 @@
 package lombok.javac;
 
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.PrintStream;
+
 import lombok.javac.JavacAST.Node;
 
 import com.sun.tools.javac.tree.JCTree;
@@ -66,16 +70,31 @@ public interface JavacASTVisitor {
 	void visitStatement(Node statementNode, JCTree statement);
 	void endVisitStatement(Node statementNode, JCTree statement);
 	
-	public static class JavacASTPrinter implements JavacASTVisitor {
+	public static class Printer implements JavacASTVisitor {
+		private final PrintStream out;
+		
+		public Printer() {
+			this(System.out);
+		}
+		
+		public Printer(File file) throws FileNotFoundException {
+			this(new PrintStream(file));
+		}
+		
+		public Printer(PrintStream out) {
+			this.out = out;
+		}
+		
 		int indent = 0;
 		private void print(String text, Object... params) {
 			StringBuilder sb = new StringBuilder();
 			for ( int i = 0 ; i < indent ; i++ ) sb.append("  ");
-			System.out.printf(sb.append(text).append('\n').toString(), params);
+			out.printf(sb.append(text).append('\n').toString(), params);
+			out.flush();
 		}
 		
 		@Override public void visitCompilationUnit(Node Node, JCCompilationUnit unit) {
-			System.out.println("---------------------------------------------------------");
+			out.println("---------------------------------------------------------");
 			
 			print("<CU %s>", Node.getFileName());
 			indent++;

src/lombok/javac/handlers/HandlePrintAST.java

@@ -1,9 +1,14 @@
 package lombok.javac.handlers;
 
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.PrintStream;
+
 import org.mangosdk.spi.ProviderFor;
 
 import com.sun.tools.javac.tree.JCTree.JCAnnotation;
 
+import lombok.Lombok;
 import lombok.core.AnnotationValues;
 import lombok.core.PrintAST;
 import lombok.javac.JavacASTVisitor;
@@ -13,7 +18,16 @@ import lombok.javac.JavacAST.Node;
 @ProviderFor(JavacAnnotationHandler.class)
 public class HandlePrintAST implements JavacAnnotationHandler<PrintAST> {
 	@Override public boolean handle(AnnotationValues<PrintAST> annotation, JCAnnotation ast, Node annotationNode) {
-		annotationNode.up().traverse(new JavacASTVisitor.JavacASTPrinter());
+		PrintStream stream = System.out;
+		String fileName = annotation.getInstance().outfile();
+		if ( fileName.length() > 0 ) try {
+			stream = new PrintStream(new File(fileName));
+		} catch ( FileNotFoundException e ) {
+			Lombok.sneakyThrow(e);
+		}
+		
+		annotationNode.up().traverse(new JavacASTVisitor.Printer(stream));
+		
 		return true;
 	}
 }