diff --git a/setup.nqp b/setup.nqp
index da4afa2..c771651 100755
--- a/setup.nqp
+++ b/setup.nqp
@@ -32,6 +32,7 @@ sub MAIN() {
             'build/POST/Pattern.pir',                   'src/POST/Pattern.nqp',
             'build/Tree/Optimizer.pir',                 'src/Tree/Optimizer.nqp',
             'build/Tree/Optimizer/Pass.pir',            'src/Tree/Optimizer/Pass.nqp',
+            'build/Tree/Optimizer/Transformers.pir',    'src/Tree/Optimizer/Transformers.nqp',
             'build/Tree/Pattern.pir',                   'src/Tree/Pattern.nqp',
             'build/Tree/Pattern/Any.pir',               'src/Tree/Pattern/Any.nqp',
             'build/Tree/Pattern/Closure.pir',           'src/Tree/Pattern/Closure.nqp',
@@ -52,6 +53,7 @@ sub MAIN() {
             'build/POST/Pattern.pbc',                   'build/POST/Pattern.pir',
             'build/Tree/Optimizer.pbc',                 'build/Tree/Optimizer.pir',
             'build/Tree/Optimizer/Pass.pbc',            'build/Tree/Optimizer/Pass.pir',
+            'build/Tree/Optimizer/Transformers.pbc',    'build/Tree/Optimizer/Transformers.pir',
             'build/Tree/Pattern.pbc',                   'build/Tree/Pattern.pir',
             'build/Tree/Pattern/Any.pbc',               'build/Tree/Pattern/Any.pir',
             'build/Tree/Pattern/Closure.pbc',           'build/Tree/Pattern/Closure.pir',
@@ -79,6 +81,7 @@ sub MAIN() {
             build/POST/Pattern.pbc
             build/Tree/Optimizer.pbc
             build/Tree/Optimizer/Pass.pbc
+            build/Tree/Optimizer/Transformers.pbc
             build/Tree/Pattern.pbc
             build/Tree/Pattern/Any.pbc
             build/Tree/Pattern/Closure.pbc
diff --git a/src/Tree/Optimizer/Pass.nqp b/src/Tree/Optimizer/Pass.nqp
index db4677c..e9105e3 100644
--- a/src/Tree/Optimizer/Pass.nqp
+++ b/src/Tree/Optimizer/Pass.nqp
@@ -1,6 +1,11 @@
 class Tree::Optimizer::Pass;
 
+INIT {
+    pir::load_bytecode('Tree/Optimizer/Transformers.pbc');
+}
+
 has $!name;
+has $!recursive;
 has $!transformation;
 has $!when;
 
@@ -22,14 +27,17 @@ my $current-gen-name := 0;
 sub gen-name () {
     '__unnamed_' ~ $current-gen-name++;
 }
-method BUILD (:$transformation, :$name, :$when, *%ignored) {
+method BUILD (:$transformation, :$name, :$recursive, :$when, *%ignored) {
     $!name := $name || gen-name();
+    $!recursive := $recursive || 0;
     $!transformation := $transformation;
     $!when := $when;
 }
 
 method run ($tree) {
-    if pir::defined__IPP($!when) {
+    if $!recursive {
+        self.generate-transformer.walk($tree);
+    } elsif pir::defined__IPP($!when) {
         my $/ := $tree ~~ $!when;
         if $/ {
             $!transformation($/);
@@ -40,3 +48,11 @@ method run ($tree) {
         $!transformation($tree);
     }
 }
+
+method generate-transformer () {
+    if pir::defined__IP($!when) {
+        $!when.transformer_class.new($!when, $!transformation);
+    } else {
+        Tree::Optimizer::Transformer::Single.new($!transformation);
+    }
+}
diff --git a/src/Tree/Optimizer/Transformers.nqp b/src/Tree/Optimizer/Transformers.nqp
new file mode 100644
index 0000000..c96b53d
--- /dev/null
+++ b/src/Tree/Optimizer/Transformers.nqp
@@ -0,0 +1,25 @@
+INIT {
+    pir::load_bytecode('Tree/Transformer.pbc');
+}
+
+class Tree::Optimizer::Transformer::Single is Tree::Transformer {
+    has $!transform;
+
+    method new ($transform) {
+        my $self := pir::new__PP(self.HOW.get_parrotclass(self));
+        $self.BUILD($transform);
+        $self;
+    }
+
+    method BUILD ($transform) { $!transform := $transform; }
+
+    method transform () { $!transform; }
+}
+
+module Tree::Walker {
+    our multi walk (Tree::Optimizer::Transformer::Single $walker, $node) {
+        my $result := $walker.transform()($node);
+        replaceChildren($result, walkChildren($walker, $result));
+        $result;
+    }
+}