diff --git a/.gitignore b/.gitignore
index b3f9a48..ed1c4c5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,4 +3,5 @@ docs.json
 __dummy.html
 *.o
 *.obj
-ddbus
+/ddbus
+__test__library__
diff --git a/dub.json b/dub.json
index c29dae0..808df83 100644
--- a/dub.json
+++ b/dub.json
@@ -7,5 +7,6 @@
   "authors": ["Tristan Hume"],
     "lflags": ["-ldbus-1"],
 	"dependencies": {
+      "dunit": "~>1.0.10"
 	}
 }
diff --git a/dub.selections.json b/dub.selections.json
index 22b6c56..a115f1d 100644
--- a/dub.selections.json
+++ b/dub.selections.json
@@ -1,4 +1,6 @@
 {
 	"fileVersion": 1,
-	"versions": {}
+	"versions": {
+		"dunit": "1.0.10"
+	}
 }
\ No newline at end of file
diff --git a/source/ddbus/thin.d b/source/ddbus/thin.d
new file mode 100644
index 0000000..2e56e68
--- /dev/null
+++ b/source/ddbus/thin.d
@@ -0,0 +1,16 @@
+module ddbus.thin;
+
+import ddbus.c_lib;
+import std.string;
+
+struct Message {
+  this(string dest, string path, string iface, string method) {
+    msg = dbus_message_new_method_call(dest.toStringz(), path.toStringz(), iface.toStringz(), method.toStringz());
+  }
+
+  ~this() {
+    dbus_message_unref(msg);
+  }
+
+  DBusMessage *msg;
+}
diff --git a/source/ddbus/util.d b/source/ddbus/util.d
new file mode 100644
index 0000000..29ccb12
--- /dev/null
+++ b/source/ddbus/util.d
@@ -0,0 +1,102 @@
+module ddbus.util;
+import std.typecons;
+import std.range;
+
+template allCanDBus(TS...) {
+  static if (TS.length == 0) {
+    enum allCanDBus = true; 
+  } else static if(!canDBus!(TS[0])) {
+    enum allCanDBus = false;
+  } else {
+    enum allCanDBus = allCanDBus!(TS[1..$]);
+  }
+}
+
+template canDBus(T) {
+  static if(is(T == byte) || is(T == short) || is (T == ushort) || is (T == int)
+            || is (T == uint) || is (T == long) || is (T == ulong)
+            || is (T == double) || is (T == string) || is(T == bool)) {
+    enum canDBus = true;
+    
+  } else static if(isTuple!T) {
+    enum canDBus = allCanDBus!(T.Types);
+  } else static if(isInputRange!T) {
+    enum canDBus = canDBus!(ElementType!T);
+  } else {
+    enum canDBus = false;
+  }
+}
+unittest {
+  import dunit.toolkit;
+  (canDBus!int).assertTrue();
+  (canDBus!(int[])).assertTrue();
+  (allCanDBus!(int,string,bool)).assertTrue();
+  (canDBus!(Tuple!(int[],bool))).assertTrue();
+  (canDBus!(Tuple!(int[],int[string]))).assertFalse();
+  (canDBus!(int[string])).assertFalse();
+}
+
+string typeSig(T)() if(canDBus!T) {
+  static if(is(T == byte)) {
+    return "y";
+  } else static if(is(T == bool)) {
+    return "b";
+  } else static if(is(T == short)) {
+    return "n";
+  } else static if(is(T == ushort)) {
+    return "q";
+  } else static if(is(T == int)) {
+    return "i";
+  } else static if(is(T == uint)) {
+    return "u";
+  } else static if(is(T == long)) {
+    return "x";
+  } else static if(is(T == ulong)) {
+    return "t";
+  } else static if(is(T == double)) {
+    return "d";
+  } else static if(is(T == string)) {
+    return "s";
+  } else static if(isTuple!T) {
+    string sig = "(";
+    foreach(i, S; T.Types) {
+      sig ~= typeSig!S();
+    } 
+    sig ~= ")";
+    return sig;
+  } else static if(isInputRange!T) {
+    return "a" ~ typeSig!(ElementType!T)();
+  }
+}
+
+string typeSigAll(TS...)() if(allCanDBus!TS) {
+  string sig = "";
+  foreach(i,T; TS) {
+    sig ~= typeSig!T();
+  }
+  return sig;
+}
+
+unittest {
+  import dunit.toolkit;
+  // basics
+  typeSig!int().assertEqual("i");
+  typeSig!bool().assertEqual("b");
+  typeSig!string().assertEqual("s");
+  // structs
+  typeSig!(Tuple!(int,string,string)).assertEqual("(iss)");
+  typeSig!(Tuple!(int,string,Tuple!(int,"k",double,"x"))).assertEqual("(is(id))");
+  // arrays
+  typeSig!(int[]).assertEqual("ai");
+  typeSig!(Tuple!(byte)[][]).assertEqual("aa(y)");
+  // multiple arguments
+  typeSigAll!(int,bool).assertEqual("ib");
+  // ctfe-capable
+  static string sig = typeSig!ulong();
+  sig.assertEqual("t");
+  static string sig2 = typeSig!(Tuple!(int,string,string));
+  sig2.assertEqual("(iss)"); 
+  static string sig3 = typeSigAll!(int,string,string);
+  sig3.assertEqual("iss"); 
+}
+