diff --git a/sources/zweic/Printer.scala b/sources/zweic/Printer.scala
new file mode 100755
index 0000000..4fad2d0
--- /dev/null
+++ b/sources/zweic/Printer.scala
@@ -0,0 +1,98 @@
+/*  zweic -- a compiler for Zwei
+ *
+ *  Stephane Micheloud & LAMP
+ *
+ *  $Id$
+ */
+
+package zweic;
+
+import java.io.PrintWriter;
+
+
+/**
+ * This class implements a pretty printer for abstract syntax
+ * trees in Zwei.
+ */
+class Printer(out: PrintWriter) {
+  import Operators._;
+
+  /**
+   * Indentation string.
+   */
+  private val step = "  ";
+
+  /**
+   * indentation level.
+   */
+  private var level = 0;
+
+  /**
+   * Prints a tree node.
+   */
+  def print(tree: Tree): Printer = tree match {
+    case Program(decls, main) =>
+      for (val d <- decls)
+        print(d).println;
+      print(main).println
+    // ... � compl�ter ...
+    case Select(prefix, selector) =>
+      print(prefix).print(".").print(selector)
+  }
+
+  /**
+   * Print abstract syntax trees separated by commas.
+   */
+  private def print(trees: List[Tree]): Printer = trees match {
+    // ... � compl�ter ...
+    case _ => this
+  }
+
+  /**
+   * Print a string.
+   */
+  private def print(value: String): Printer = {
+    out.print(value);
+    this
+  }
+
+  private def print(name: Name): Printer = print(name.name);
+
+  private def print(formal: Pair[Name, TypeTree]): Printer =
+    print(formal._2).print(" ").print(formal._1);
+
+  /**
+   * Print abstract syntax trees separated by commas.
+   */
+  private def printFormals(formals: List[Pair[Name, TypeTree]]): Printer =
+    formals match {
+      // ... � compl�ter ...
+      case _ => this
+    }
+
+  /**
+   * Print an end-of-line character and indent the following
+   * line appropriately.
+   */
+  private def println = {
+    out.println();
+    for (val i <- List.range(0, level)) out.print(step);
+    this
+  }
+
+  /**
+   * Increment the indentation level.
+   */
+  private def indent = {
+    level = level + 1;
+    this
+  }
+
+  /**
+   * Decrement the indentation level.
+   */
+  private def undent = {
+    level = level - 1;
+    this
+  }
+}
diff --git a/sources/zweic/PrinterTest.scala b/sources/zweic/PrinterTest.scala
new file mode 100755
index 0000000..771f7db
--- /dev/null
+++ b/sources/zweic/PrinterTest.scala
@@ -0,0 +1,45 @@
+/*  zweic -- a compiler for Zwei
+ *
+ *  Stephane Micheloud & LAMP
+ *
+ *  $Id$
+ */
+
+package zweic;
+
+
+/**
+ * A small test class for the pretty printer of zweic; it reads in a
+ * file and prints out the abstract syntax tree. If the program is
+ * erroneous, the compiler will print a corresponding error message
+ * instead.
+ *
+ * usage: scala zweic.PrinterTest <file.zwei>
+ */
+object PrinterTest {
+  import java.io.{FileInputStream, FileWriter, PrintWriter, IOException};
+
+  def main(args: Array[String]): Unit = {
+    if (args.length == 0) {
+      Console.println("usage: scala zweic.PrinterTest <file.zwei>");
+      System.exit(1)
+    }
+    try {
+      val in = new FileInputStream(args(0));
+      val tree = new Parser(in).parse;
+      in.close();
+      if (Report.errors > 0)
+        System.err.println(Report.errors + " errors found." );
+      else {
+        val out = if (args.length < 2) new PrintWriter(System.out)
+                  else new PrintWriter(new FileWriter(args(1)));
+        new Printer(out).print(tree);
+        out.close();
+      }
+      System.exit(if (Report.errors > 0) 1 else 0);
+    }
+    catch {
+      case e: IOException => Report.fail(e.getMessage());
+    }
+  }
+}