Last round of simplification of Signal/Slot classes

- merged all the common stuff from 0,1,2,3 argument versions into one common base class
- removed ReturnType template parameter as it was instantiated with "void" everywhere and the
  current ignores the return value of the callbacks anyway

src/ButtonTheme.hh

@@ -43,7 +43,7 @@ public:
     int scale() const { return *m_scale; } // scale factor for inside objects
     const std::string &name() { return m_name; }
 
-    virtual FbTk::Signal<void> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
+    virtual FbTk::Signal<> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
 
     virtual ButtonTheme &operator *() { return *this; }
     virtual const ButtonTheme &operator *() const { return *this; }

src/FbTk/MenuTheme.hh

@@ -130,7 +130,7 @@ public:
             m_hl_selected_pixmap->pixmap().dontFree();
     }
 
-    virtual Signal<void> &reconfigSig() { return Theme::reconfigSig(); }
+    virtual Signal<> &reconfigSig() { return Theme::reconfigSig(); }
 
     virtual MenuTheme &operator *() { return *this; }
     virtual const MenuTheme &operator *() const { return *this; }

src/FbTk/Signal.hh

@@ -22,7 +22,6 @@
 #ifndef FBTK_SIGNAL_HH
 #define FBTK_SIGNAL_HH
 
-#include "RefCount.hh"
 #include "Slot.hh"
 #include <algorithm>
 #include <list>
@@ -35,7 +34,7 @@ namespace FbTk {
 namespace SigImpl {
 
 /**
- * Parent class for all \c Signal[0...*] classes.
+ * Parent class for all \c Signal template classes.
  * It handles the disconnect and holds all the slots. The connect must be
  * handled by the child class so it can do the type checking.
  */
@@ -121,93 +120,66 @@ private:
     unsigned m_emitting;
 };
 
-struct EmptyArg {};
+template <typename Arg1, typename Arg2, typename Arg3>
+class SignalTemplate: public SignalHolder {
+public:
+    template<typename Functor>
+    SlotID connect(const Functor& functor) {
+        return SignalHolder::connect(SlotPtr( new Slot<Arg1, Arg2, Arg3, Functor>(functor) ));
+    }
+
+protected:
+    void emit_(Arg1 arg1, Arg2 arg2, Arg3 arg3) {
+        begin_emitting();
+        for ( Iterator it = begin(); it != end(); ++it ) {
+            if(*it)
+                static_cast<SigImpl::SlotTemplate<Arg1, Arg2, Arg3> &>(**it)(arg1, arg2, arg3);
+        }
+        end_emitting();
+    }
+};
 
 } // namespace SigImpl
 
 
-/// Specialization for three arguments.
+/// Base template for three arguments.
-template <typename ReturnType,
+template <typename Arg1 = SigImpl::EmptyArg, typename Arg2 = SigImpl::EmptyArg, typename Arg3 = SigImpl::EmptyArg >
-          typename Arg1 = SigImpl::EmptyArg, typename Arg2 = SigImpl::EmptyArg, typename Arg3 = SigImpl::EmptyArg >
+class Signal: public SigImpl::SignalTemplate<Arg1, Arg2, Arg3> {
-class Signal: public SigImpl::SignalHolder {
 public:
-    void emit(Arg1 arg1, Arg2 arg2, Arg3 arg3) {
+    void emit(Arg1 arg1, Arg2 arg2, Arg3 arg3)
-        begin_emitting();
+    { SigImpl::SignalTemplate<Arg1, Arg2, Arg3>::emit_(arg1, arg2, arg3); }
-        for ( Iterator it = begin(); it != end(); ++it ) {
-            if(*it)
-                static_cast<SigImpl::SlotBase3<ReturnType, Arg1, Arg2, Arg3> &>(**it)(arg1, arg2, arg3);
-        }
-        end_emitting();
-    }
-
-    template<typename Functor>
-    SlotID connect(const Functor& functor) {
-        return SignalHolder::connect(SlotPtr(
-                        new SigImpl::Slot3<ReturnType, Arg1, Arg2, Arg3, Functor>(functor)
-                    ));
-    }
 };
 
 /// Specialization for two arguments.
-template <typename ReturnType, typename Arg1, typename Arg2>
+template <typename Arg1, typename Arg2>
-class Signal<ReturnType, Arg1, Arg2, SigImpl::EmptyArg>: public SigImpl::SignalHolder {
+class Signal<Arg1, Arg2, SigImpl::EmptyArg>:
+        public SigImpl::SignalTemplate<Arg1, Arg2, SigImpl::EmptyArg> {
 public:
     void emit(Arg1 arg1, Arg2 arg2) {
-        begin_emitting();
+        SigImpl::SignalTemplate<Arg1, Arg2, SigImpl::EmptyArg>::
-        for ( Iterator it = begin(); it != end(); ++it ) {
+            emit_(arg1, arg2, SigImpl::EmptyArg());
-            if(*it)
-                static_cast<SigImpl::SlotBase2<ReturnType, Arg1, Arg2> &>(**it)(arg1, arg2);
-        }
-        end_emitting();
-    }
-
-    template<typename Functor>
-    SlotID connect(const Functor& functor) {
-        return SignalHolder::connect(SlotPtr(
-                        new SigImpl::Slot2<ReturnType, Arg1, Arg2, Functor>(functor)
-                    ));
     }
 };
 
 /// Specialization for one argument.
-template <typename ReturnType, typename Arg1>
+template <typename Arg1>
-class Signal<ReturnType, Arg1, SigImpl::EmptyArg, SigImpl::EmptyArg>: public SigImpl::SignalHolder {
+class Signal<Arg1, SigImpl::EmptyArg, SigImpl::EmptyArg>:
+        public SigImpl::SignalTemplate<Arg1, SigImpl::EmptyArg, SigImpl::EmptyArg> {
 public:
-    void emit(Arg1 arg) {
+    void emit(Arg1 arg1) {
-        begin_emitting();
+        SigImpl::SignalTemplate<Arg1, SigImpl::EmptyArg, SigImpl::EmptyArg>
-        for ( Iterator it = begin(); it != end(); ++it ) {
+            ::emit_(arg1, SigImpl::EmptyArg(), SigImpl::EmptyArg());
-            if(*it)
-                static_cast<SigImpl::SlotBase1<ReturnType, Arg1> &>(**it)(arg);
-        }
-        end_emitting();
-    }
-
-    template<typename Functor>
-    SlotID connect(const Functor& functor) {
-        return SignalHolder::connect(SlotPtr(
-                        new SigImpl::Slot1<ReturnType, Arg1, Functor>(functor)
-                    ));
     }
 };
 
 /// Specialization for no arguments.
-template <typename ReturnType>
+template <>
-class Signal<ReturnType, SigImpl::EmptyArg, SigImpl::EmptyArg, SigImpl::EmptyArg>: public SigImpl::SignalHolder {
+class Signal<SigImpl::EmptyArg, SigImpl::EmptyArg, SigImpl::EmptyArg>:
+        public SigImpl::SignalTemplate<SigImpl::EmptyArg, SigImpl::EmptyArg, SigImpl::EmptyArg> {
 public:
     void emit() {
-        begin_emitting();
+        SigImpl::SignalTemplate<SigImpl::EmptyArg, SigImpl::EmptyArg, SigImpl::EmptyArg>
-        for ( Iterator it = begin(); it != end(); ++it ) {
+            ::emit_(SigImpl::EmptyArg(), SigImpl::EmptyArg(), SigImpl::EmptyArg());
-            if(*it)
-                static_cast<SigImpl::SlotBase0<ReturnType> &>(**it)();
-        }
-        end_emitting();
-    }
-
-    template<typename Functor>
-    SlotID connect(const Functor& functor) {
-        return SignalHolder::connect(SlotPtr(
-                        new SigImpl::Slot0<ReturnType, Functor>(functor)
-                    ));
     }
 };
 

src/FbTk/Slot.hh

@@ -22,81 +22,72 @@
 #ifndef FBTK_SLOT_HH
 #define FBTK_SLOT_HH
 
+#include "RefCount.hh"
+
 namespace FbTk {
 
 /// \namespace Implementation details for signals, do not use anything in this namespace
 namespace SigImpl {
 
+struct EmptyArg {};
+
 class SlotBase {
 public:
     virtual ~SlotBase() {}
 };
 
-template<typename ReturnType>
+template<typename Arg1, typename Arg2, typename Arg3>
-class SlotBase0: public SlotBase {
+class SlotTemplate: public SlotBase {
 public:
-    virtual ReturnType operator()() = 0;
+    virtual void operator()(Arg1, Arg2, Arg3) = 0;
 };
 
-template<typename ReturnType, typename Functor>
+template<typename Arg1, typename Arg2, typename Arg3, typename Functor>
-class Slot0: public SlotBase0<ReturnType> {
+class Slot: public SlotTemplate<Arg1, Arg2, Arg3> {
 public:
-    virtual ReturnType operator()() { return m_functor(); }
+    virtual void operator()(Arg1 arg1, Arg2 arg2, Arg3 arg3)
+    { m_functor(arg1, arg2, arg3); }
 
-    Slot0(Functor functor) : m_functor(functor) {}
+    Slot(Functor functor) : m_functor(functor) {}
 
 private:
     Functor m_functor;
 };
 
-template<typename ReturnType, typename Arg1>
+// specialization for two arguments
-class SlotBase1: public SlotBase {
+template<typename Arg1, typename Arg2, typename Functor>
+class Slot<Arg1, Arg2, EmptyArg, Functor>: public SlotTemplate<Arg1, Arg2, EmptyArg> {
 public:
-    virtual ReturnType operator()(Arg1) = 0;
+    virtual void operator()(Arg1 arg1, Arg2 arg2, EmptyArg)
-};
+    { m_functor(arg1, arg2); }
 
-template<typename ReturnType, typename Arg1, typename Functor>
+    Slot(Functor functor) : m_functor(functor) {}
-class Slot1: public SlotBase1<ReturnType, Arg1> {
-public:
-    virtual ReturnType operator()(Arg1 arg1) { return m_functor(arg1); }
-
-    Slot1(Functor functor) : m_functor(functor) {}
 
 private:
     Functor m_functor;
 };
 
-template<typename ReturnType, typename Arg1, typename Arg2>
+// specialization for one argument
-class SlotBase2: public SlotBase {
+template<typename Arg1, typename Functor>
+class Slot<Arg1, EmptyArg, EmptyArg, Functor>: public SlotTemplate<Arg1, EmptyArg, EmptyArg> {
 public:
-    virtual ReturnType operator()(Arg1, Arg2) = 0;
+    virtual void operator()(Arg1 arg1, EmptyArg, EmptyArg)
-};
+    { m_functor(arg1); }
 
-template<typename ReturnType, typename Arg1, typename Arg2, typename Functor>
+    Slot(Functor functor) : m_functor(functor) {}
-class Slot2: public SlotBase2<ReturnType, Arg1, Arg2> {
-public:
-    virtual ReturnType operator()(Arg1 arg1, Arg2 arg2) { return m_functor(arg1, arg2); }
-
-    Slot2(Functor functor) : m_functor(functor) {}
 
 private:
     Functor m_functor;
 };
 
-template<typename ReturnType, typename Arg1, typename Arg2, typename Arg3>
+// specialization for no arguments
-class SlotBase3: public SlotBase {
+template<typename Functor>
+class Slot<EmptyArg, EmptyArg, EmptyArg, Functor>: public SlotTemplate<EmptyArg, EmptyArg, EmptyArg> {
 public:
-    virtual ReturnType operator()(Arg1, Arg2, Arg3) = 0;
+    virtual void operator()(EmptyArg, EmptyArg, EmptyArg)
-    virtual ~SlotBase3() {}
+    { m_functor(); }
-};
 
-template<typename ReturnType, typename Arg1, typename Arg2, typename Arg3, typename Functor>
+    Slot(Functor functor) : m_functor(functor) {}
-class Slot3: public SlotBase3<ReturnType, Arg1, Arg2, Arg3> {
-public:
-    virtual ReturnType operator()(Arg1 arg1, Arg2 arg2, Arg3 arg3)
-    { return m_functor(arg1, arg2, arg3); }
-
-    Slot3(Functor functor) : m_functor(functor) {}
 
 private:
     Functor m_functor;
@@ -106,4 +97,5 @@ private:
 
 } // namespace FbTk
 
+
 #endif // FBTK_SLOT_H

src/FbTk/Theme.hh

@@ -107,13 +107,13 @@ public:
     template <typename T>
     void remove(ThemeItem<T> &item);
     virtual bool fallback(ThemeItem_base &) { return false; }
-    Signal<void> &reconfigSig() { return m_reconfig_sig; }
+    Signal<> &reconfigSig() { return m_reconfig_sig; }
 
 private:
     const int m_screen_num;
 
     ItemList m_themeitems;
-    Signal<void> m_reconfig_sig;
+    Signal<> m_reconfig_sig;
 };
 
 /// Proxy interface for themes, so they can be substituted dynamically
@@ -122,7 +122,7 @@ class ThemeProxy {
 public:
     virtual ~ThemeProxy() { }
 
-    virtual Signal<void> &reconfigSig() = 0;
+    virtual Signal<> &reconfigSig() = 0;
 
     virtual BaseTheme &operator *() = 0;
     virtual const BaseTheme &operator *() const = 0;

src/FbWinFrameTheme.hh

@@ -79,7 +79,7 @@ public:
 
     IconbarTheme &iconbarTheme() { return m_iconbar_theme; }
 
-    virtual FbTk::Signal<void> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
+    virtual FbTk::Signal<> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
 
     virtual FbWinFrameTheme &operator *() { return *this; }
     virtual const FbWinFrameTheme &operator *() const { return *this; }

src/Focusable.hh

@@ -119,13 +119,13 @@ public:
        @name signals
        @{
     */
-    typedef FbTk::Signal<void, const std::string&, Focusable&> TitleSignal;
+    typedef FbTk::Signal<const std::string&, Focusable&> TitleSignal;
     /// Used for both title and icon changes.
     TitleSignal &titleSig() { return m_titlesig; }
     /// Used for both title and icon changes.
     const TitleSignal &titleSig() const { return m_titlesig; }
-    FbTk::Signal<void, Focusable&> &focusSig() { return m_focussig; }
+    FbTk::Signal<Focusable&> &focusSig() { return m_focussig; }
-    const FbTk::Signal<void, Focusable&> &focusSig() const { return m_focussig; }
+    const FbTk::Signal<Focusable&> &focusSig() const { return m_focussig; }
     FbTk::Subject &dieSig() { return m_diesig; }
     const FbTk::Subject &dieSig() const { return m_diesig; }
     FbTk::Subject &attentionSig() { return m_attentionsig; }
@@ -153,7 +153,7 @@ protected:
     FocusSubject m_diesig, m_attentionsig;
 
 private:
-    FbTk::Signal<void, Focusable&> m_focussig;
+    FbTk::Signal<Focusable&> m_focussig;
     TitleSignal m_titlesig;
 };
 

src/FocusableTheme.hh

@@ -36,13 +36,13 @@ public:
         m_win(win), m_focused_theme(focused), m_unfocused_theme(unfocused) {
 
         m_signals.join(m_win.focusSig(),
-                FbTk::MemFunIgnoreArgs(m_reconfig_sig, &FbTk::Signal<void>::emit));
+                FbTk::MemFunIgnoreArgs(m_reconfig_sig, &FbTk::Signal<>::emit));
 
         m_win.attentionSig().attach(this);
         m_signals.join(m_focused_theme.reconfigSig(),
-                FbTk::MemFun(m_reconfig_sig, &FbTk::Signal<void>::emit));
+                FbTk::MemFun(m_reconfig_sig, &FbTk::Signal<>::emit));
         m_signals.join(m_unfocused_theme.reconfigSig(),
-                FbTk::MemFun(m_reconfig_sig, &FbTk::Signal<void>::emit));
+                FbTk::MemFun(m_reconfig_sig, &FbTk::Signal<>::emit));
     }
 
     Focusable &win() { return m_win; }
@@ -54,7 +54,7 @@ public:
     FbTk::ThemeProxy<BaseTheme> &unfocusedTheme() { return m_unfocused_theme; }
     const FbTk::ThemeProxy<BaseTheme> &unfocusedTheme() const { return m_unfocused_theme; }
 
-    FbTk::Signal<void> &reconfigSig() { return m_reconfig_sig; }
+    FbTk::Signal<> &reconfigSig() { return m_reconfig_sig; }
 
     virtual BaseTheme &operator *() {
         return (m_win.isFocused() || m_win.getAttentionState()) ?
@@ -70,7 +70,7 @@ private:
 
     Focusable &m_win;
     FbTk::ThemeProxy<BaseTheme> &m_focused_theme, &m_unfocused_theme;
-    FbTk::Signal<void> m_reconfig_sig;
+    FbTk::Signal<> m_reconfig_sig;
     FbTk::SignalTracker m_signals;
 };
 

src/IconbarTheme.hh

@@ -41,7 +41,7 @@ public:
     const FbTk::Texture &texture() const { return *m_texture; }
     const FbTk::Texture &emptyTexture() const { return *m_empty_texture; }
 
-    virtual FbTk::Signal<void> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
+    virtual FbTk::Signal<> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
 
     virtual IconbarTheme &operator *() { return *this; }
     virtual const IconbarTheme &operator *() const { return *this; }

src/RootTheme.hh

@@ -48,7 +48,7 @@ public:
 
     GC opGC() const { return m_opgc.gc(); }
 
-    virtual FbTk::Signal<void> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
+    virtual FbTk::Signal<> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
 
     virtual RootTheme &operator *() { return *this; }
     virtual const RootTheme &operator *() const { return *this; }

src/Screen.hh

@@ -197,7 +197,7 @@ public:
        @name Screen signals
     */
     //@{
-    typedef FbTk::Signal<void, BScreen&> ScreenSignal;
+    typedef FbTk::Signal<BScreen&> ScreenSignal;
     /// client list signal
     ScreenSignal &clientListSig() { return m_clientlist_sig; }
     /// icon list sig
@@ -211,7 +211,7 @@ public:
     /// current workspace signal
     ScreenSignal &currentWorkspaceSig() { return m_currentworkspace_sig; }
     /// focused window signal
-    FbTk::Signal<void, BScreen&, FluxboxWindow*, WinClient*> &focusedWindowSig() { return m_focusedwindow_sig; }
+    FbTk::Signal<BScreen&, FluxboxWindow*, WinClient*> &focusedWindowSig() { return m_focusedwindow_sig; }
     /// reconfigure signal
     FbTk::Subject &reconfigureSig() { return m_reconfigure_sig; }
     ScreenSignal &resizeSig() { return m_resize_sig; }
@@ -479,7 +479,7 @@ private:
     ScreenSubject m_reconfigure_sig; ///< reconfigure signal
 
 
-    FbTk::Signal<void, BScreen&, FluxboxWindow*, WinClient*> m_focusedwindow_sig;  ///< focused window signal
+    FbTk::Signal<BScreen&, FluxboxWindow*, WinClient*> m_focusedwindow_sig;  ///< focused window signal
     ScreenSignal m_resize_sig; ///< resize signal
     ScreenSignal m_workspace_area_sig; ///< workspace area changed signal
     ScreenSignal m_iconlist_sig; ///< notify if a window gets iconified/deiconified

src/SlitTheme.hh

@@ -38,7 +38,7 @@ public:
     int borderWidth() const { return *m_border_width; }
     int bevelWidth() const { return *m_bevel_width; }
 
-    virtual FbTk::Signal<void> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
+    virtual FbTk::Signal<> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
 
     virtual SlitTheme &operator *() { return *this; }
     virtual const SlitTheme &operator *() const { return *this; }

src/ToolTheme.hh

@@ -43,7 +43,7 @@ public:
     int alpha() const { return m_alpha; }
     void setAlpha(int alpha) { m_alpha = alpha; }
 
-    virtual FbTk::Signal<void> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
+    virtual FbTk::Signal<> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
 
     virtual ToolTheme &operator *() { return *this; }
     virtual const ToolTheme &operator *() const { return *this; }

src/ToolbarTheme.hh

@@ -44,7 +44,7 @@ public:
     int height() const { return *m_height; }
     int buttonSize() const { return *m_button_size; }
 
-    virtual FbTk::Signal<void> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
+    virtual FbTk::Signal<> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
 
     virtual ToolbarTheme &operator *() { return *this; }
     virtual const ToolbarTheme &operator *() const { return *this; }

src/WinButtonTheme.hh

@@ -65,7 +65,7 @@ public:
     FbTk::PixmapWithMask &titlePixmap() { return *m_title_pm; }
     const FbTk::PixmapWithMask &titlePixmap() const { return *m_title_pm; }
 
-    virtual FbTk::Signal<void> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
+    virtual FbTk::Signal<> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
 
     virtual WinButtonTheme &operator *() { return *this; }
     virtual const WinButtonTheme &operator *() const { return *this; }

src/Workspace.hh

@@ -85,7 +85,7 @@ private:
     BScreen &m_screen;
 
     Windows m_windowlist;
-    FbTk::Signal<void> m_clientlist_sig;
+    FbTk::Signal<> m_clientlist_sig;
     ClientMenu m_clientmenu;
 
     FbTk::FbString m_name;  ///< name of this workspace

src/WorkspaceNameTheme.hh

@@ -49,7 +49,7 @@ public:
         return ToolTheme::fallback(item);
     }
 
-    virtual FbTk::Signal<void> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
+    virtual FbTk::Signal<> &reconfigSig() { return FbTk::Theme::reconfigSig(); }
 
     virtual WorkspaceNameTheme &operator *() { return *this; }
     virtual const WorkspaceNameTheme &operator *() const { return *this; }

src/tests/testSignals.cc

@@ -80,16 +80,16 @@ int main() {
     using FbTk::Signal;
     using FbTk::SignalTracker;
 
-    Signal<void> no_arg;
+    Signal<> no_arg;
     no_arg.connect( NoArgument() );
 
-    Signal<void, int> one_arg;
+    Signal<int> one_arg;
     one_arg.connect( OneArgument() );
 
-    Signal<void, int, const string&> two_args;
+    Signal<int, const string&> two_args;
     two_args.connect( TwoArguments() );
     
-    Signal<void, int, const string&, double> three_args;
+    Signal<int, const string&, double> three_args;
     three_args.connect( ThreeArguments() );
 
     // emit test
@@ -127,7 +127,7 @@ int main() {
     no_arg.emit();
 
     string takeThis("Take this");
-    Signal<void, string&> ref_arg;
+    Signal<string&> ref_arg;
     ref_arg.connect(MemFun(obj, &FunctionClass::takeIt));
     ref_arg.emit( takeThis );
 
@@ -145,7 +145,7 @@ int main() {
         using FbTk::MemFunIgnoreArgs;
         // Create a signal that emits with three arguments, and connect
         // sinks that takes less than three arguments.
-        Signal<void, string, string, float> more_args;
+        Signal<string, string, float> more_args;
         more_args.connect(MemFunIgnoreArgs(obj, &FunctionClass::print));
         more_args.connect(MemFunIgnoreArgs(obj, &FunctionClass::takeIt));
         more_args.connect(MemFunIgnoreArgs(obj, &FunctionClass::showMessage2));
@@ -168,7 +168,7 @@ int main() {
         destination.attach(&obs);
         // create a new signal and relay it to the
         // old subject
-        FbTk::Signal<void, string> source;
+        FbTk::Signal<string> source;
         FbTk::relaySignal(source, destination);
         // the new signal should now make the old
         // subject notify its observers
@@ -178,7 +178,7 @@ int main() {
     // Test argument selector
     {
         using namespace FbTk;
-        Signal<void, int, string, float> source;
+        Signal<int, string, float> source;
 
         Printer printer;
         source.connect(MemFunSelectArg0(printer, &Printer::printInt));
@@ -187,7 +187,7 @@ int main() {
 
         source.emit(10, "hello", 3.141592);
 
-        Signal<void, string, int> source2;
+        Signal<string, int> source2;
         source2.connect(MemFunSelectArg0(printer, &Printer::printString));
         source2.connect(MemFunSelectArg1(printer, &Printer::printInt));
         source2.emit("world", 37);