diff --git a/vala/clone_gee_iterator/clone_gee_iterator.vala b/vala/clone_gee_iterator/clone_gee_iterator.vala
new file mode 100644
index 0000000..09533da
--- /dev/null
+++ b/vala/clone_gee_iterator/clone_gee_iterator.vala
@@ -0,0 +1,18 @@
+void main () {
+	var l = new Gee.ArrayList<string> ();
+
+	for (var i = 0; i < 8; ++i)
+		l.add (i.to_string ());
+
+	var it = l.bidir_list_iterator (),
+		it2 = l.bidir_list_iterator ();
+	it2.first ();
+	for (var has_next = it.first (); has_next; has_next = it.next ()) {
+		it2 = it;//.set (it.index ());
+		var it3 = it2.copy ();
+		stdout.printf ("%s", it2.get ());
+		stdout.printf (" ");
+		stdout.printf ("%lu %lu", (ulong)it, (ulong)it2);
+		stdout.printf ("\n");
+	}
+}
diff --git a/vala/construct/construct.vala b/vala/construct/construct.vala
new file mode 100644
index 0000000..1b6c6df
--- /dev/null
+++ b/vala/construct/construct.vala
@@ -0,0 +1,26 @@
+class Base : Object {
+	public int field;
+
+	public Base () {
+		field = 5;
+	}
+}
+
+class Child : Base {
+}
+
+void main () {
+	var b = new Base ();
+	var c = new Child ();
+	stdout.printf ("%d\n", c.field);
+
+	//Error *err;
+	//stdout.printf ("%s\n", err->message);
+
+	string s = "Hello, world!";
+	stdout.printf ("%s\n", s[7:s.length]);
+	for (var i = 0; s[i] != '\0' ; ++i) {
+		stdout.putc (s[i]);
+	}
+	stdout.putc ('\n');
+}
diff --git a/vala/strdup/strdup.vala b/vala/strdup/strdup.vala
new file mode 100644
index 0000000..df2b93a
--- /dev/null
+++ b/vala/strdup/strdup.vala
@@ -0,0 +1,40 @@
+class Foo {
+	public unowned string s = "";
+}
+
+public int main () {
+	var s = "Hello, world!";
+
+	var foo = new Foo ();
+
+	foo.s = s;
+
+	//string tmps = s[0:5];
+	unowned string tmps = (string)((char*)s + 3);
+
+	((char *)s)[3] = 'A';
+
+	stdout.printf ("%s\n", s);
+	stdout.printf ("%s\n", foo.s);
+
+	stdout.printf ("%s\n", tmps);
+
+	stdout.printf ("%s\n", tmps[0:1]);
+	stdout.printf ("%s\n", tmps.ndup (1));
+	stdout.printf ("%s\n", tmps.substring (2, 3));
+	stdout.printf ("%s\n", tmps[2:3]);
+	stdout.printf ("%s\n", tmps.chr (100, 'o'));
+	//stdout.printf ("%s\n", Posix.strchr (tmps, 'o'));
+
+	print ("----\n");
+	stdout.printf ("%s\n", tmps);
+	stdout.printf ("%s\n", tmps.offset (3)[0:-1]);
+
+	for (var i = 0, max_i = tmps.length; i < max_i; ++i)
+		stdout.printf ("%c", tmps[i]);
+	stdout.printf ("\n");
+
+	stdout.printf ("%p = '%s'[%u]\n", tmps.offset (100), tmps.offset (100), tmps.offset (100).length);
+
+	return 0;
+}
diff --git a/vala/switch_break/switch_break.vala b/vala/switch_break/switch_break.vala
new file mode 100644
index 0000000..b9fa6f9
--- /dev/null
+++ b/vala/switch_break/switch_break.vala
@@ -0,0 +1,19 @@
+void main () {
+	var i = 5;
+	switch (i) {
+		case 5:
+			if (i == 5) {
+				stdout.printf ("first case\n");
+				break;
+			}
+			stdout.printf ("after break\n");
+			break;
+
+		case 6:
+			stdout.printf ("second case\n");
+			break;
+
+		default:
+			break;
+	}
+}
diff --git a/vala/uninitialized/uninitialized.vala b/vala/uninitialized/uninitialized.vala
new file mode 100644
index 0000000..f4ea9f1
--- /dev/null
+++ b/vala/uninitialized/uninitialized.vala
@@ -0,0 +1,65 @@
+class Foo {
+	public void f () {
+		stdout.printf ("Hello, world!\n");
+	}
+}
+
+Foo? newf () {
+	return new Foo ();
+}
+
+void fff (string [] s) {
+	stdout.printf ("%s\n", s[0]);
+}
+
+class AA11 {
+	public enum Enum1 {
+		E1 = 1,
+		E2 = 2
+	}
+
+	public uint i;
+	public string s { get; set; default = "AA11"; }
+	public Enum1 enum1 { get; set; default = Enum1.E2; }
+}
+
+class BB11 {
+	public AA11 aa11 = new AA11 ();
+	public List<int> list = new List<int> ();
+	public Node<int> node = new Node<int> ();
+	public Gee.ArrayList<int> alist { get; set; default = new Gee.ArrayList<int> (); }
+}
+
+void main () {
+	var foo = newf ();
+
+	foo.f();
+
+	string [] s = {"Unowned string"};
+	unowned string [] us = s;
+	fff (us);
+
+	string str = "Hello, world!";
+	stdout.printf ("%s\n", str.substring(3));
+
+	var a = new AA11 ();
+	stdout.printf ("-----------\n");
+	stdout.printf ("%s, %u, %u\n", a.s, a.i, a.enum1);
+
+	var b = new BB11 ();
+	stdout.printf ("-----------\n");
+	stdout.printf ("%s, %u, %u\n", b.aa11.s, b.aa11.i, b.aa11.enum1);
+	b.list.append (3);
+	b.list.append (3);
+	b.list.append (3);
+	b.list.append (3);
+	b.node.insert (0, new Node<int> (3));
+	b.node.insert (0, new Node<int> (3));
+	stdout.printf ("%u\n", b.alist.size);
+	stdout.printf ("%u, %u\n", b.list.length(), b.node.n_nodes(TraverseFlags.ALL));
+
+	List<int> l = new List<int> ();
+	l.append (3);
+
+	var tmp = "";
+}