diff --git a/activation.cpp b/activation.cpp
index cde06b4c37..4824645911 100644
--- a/activation.cpp
+++ b/activation.cpp
@@ -695,13 +695,6 @@ void Client::demandAttention(bool set)
     emit demandsAttentionChanged();
 }
 
-// TODO I probably shouldn't be lazy here and do it without the macro, so that people can read it
-KWIN_COMPARE_PREDICATE(SameApplicationActiveHackPredicate, Client, const Client*,
-                       // ignore already existing splashes, toolbars, utilities and menus,
-                       // as the app may show those before the main window
-                       !cl->isSplash() && !cl->isToolbar() && !cl->isUtility() && !cl->isMenu()
-                       && Client::belongToSameApplication(cl, value, true) && cl != value);
-
 xcb_timestamp_t Client::readUserTimeMapTimestamp(const KStartupInfoId *asn_id, const KStartupInfoData *asn_data,
                                                  bool session) const
 {
@@ -733,17 +726,23 @@ xcb_timestamp_t Client::readUserTimeMapTimestamp(const KStartupInfoId *asn_id, c
         Client* act = workspace()->mostRecentlyActivatedClient();
         if (act != NULL && !belongToSameApplication(act, this, true)) {
             bool first_window = true;
+            auto sameApplicationActiveHackPredicate = [this](const Client *cl) {
+                // ignore already existing splashes, toolbars, utilities and menus,
+                // as the app may show those before the main window
+                return !cl->isSplash() && !cl->isToolbar() && !cl->isUtility() && !cl->isMenu()
+                        && cl != this && Client::belongToSameApplication(cl, this, true);
+            };
             if (isTransient()) {
                 if (act->hasTransient(this, true))
                     ; // is transient for currently active window, even though it's not
                 // the same app (e.g. kcookiejar dialog) -> allow activation
                 else if (groupTransient() &&
-                        findClientInList(mainClients(), SameApplicationActiveHackPredicate(this)) == NULL)
+                        findInList<Client>(mainClients(), sameApplicationActiveHackPredicate) == NULL)
                     ; // standalone transient
                 else
                     first_window = false;
             } else {
-                if (workspace()->findClient(SameApplicationActiveHackPredicate(this)))
+                if (workspace()->findClient(sameApplicationActiveHackPredicate))
                     first_window = false;
             }
             // don't refuse if focus stealing prevention is turned off
diff --git a/appmenu.cpp b/appmenu.cpp
index 2937a46ea1..d8266449c7 100644
--- a/appmenu.cpp
+++ b/appmenu.cpp
@@ -50,13 +50,13 @@ bool ApplicationMenu::hasMenu(xcb_window_t window)
 
 void ApplicationMenu::slotShowRequest(qulonglong wid)
 {
-    if (Client *c = Workspace::self()->findClient(WindowMatchPredicate(wid)))
+    if (Client *c = Workspace::self()->findClient(Predicate::WindowMatch, wid))
         c->emitShowRequest();
 }
 
 void ApplicationMenu::slotMenuAvailable(qulonglong wid)
 {
-    if (Client *c = Workspace::self()->findClient(WindowMatchPredicate(wid)))
+    if (Client *c = Workspace::self()->findClient(Predicate::WindowMatch, wid))
         c->setAppMenuAvailable();
     else
         m_windowsMenu.append(wid);
@@ -64,7 +64,7 @@ void ApplicationMenu::slotMenuAvailable(qulonglong wid)
 
 void ApplicationMenu::slotMenuHidden(qulonglong wid)
 {
-    if (Client *c = Workspace::self()->findClient(WindowMatchPredicate(wid)))
+    if (Client *c = Workspace::self()->findClient(Predicate::WindowMatch, wid))
         c->emitMenuHidden();
 }
 
diff --git a/client.cpp b/client.cpp
index 7d4ef33d8b..4a9de4a438 100644
--- a/client.cpp
+++ b/client.cpp
@@ -1800,8 +1800,6 @@ QString Client::readName() const
         return KWindowSystem::readNameProperty(window(), XCB_ATOM_WM_NAME);
 }
 
-KWIN_COMPARE_PREDICATE(FetchNameInternalPredicate, Client, const Client*, (!cl->isSpecialWindow() || cl->isToolbar()) && cl != value && cl->caption() == value->caption());
-
 // The list is taken from http://www.unicode.org/reports/tr9/ (#154840)
 QChar LRM(0x200E);
 QChar RLM(0x200F);
@@ -1856,12 +1854,16 @@ void Client::setCaption(const QString& _s, bool force)
     }
     QString shortcut_suffix = !shortcut().isEmpty() ? (QStringLiteral(" {") + shortcut().toString() + QStringLiteral("}")) : QString();
     cap_suffix = machine_suffix + shortcut_suffix;
-    if ((!isSpecialWindow() || isToolbar()) && workspace()->findClient(FetchNameInternalPredicate(this))) {
+    auto fetchNameInternalPredicate = [this](const Client *cl) {
+        return (!cl->isSpecialWindow() || cl->isToolbar()) &&
+                cl != this && cl->caption() == caption();
+    };
+    if ((!isSpecialWindow() || isToolbar()) && workspace()->findClient(fetchNameInternalPredicate)) {
         int i = 2;
         do {
             cap_suffix = machine_suffix + QStringLiteral(" <") + QString::number(i) + QStringLiteral(">") + LRM;
             i++;
-        } while (workspace()->findClient(FetchNameInternalPredicate(this)));
+        } while (workspace()->findClient(fetchNameInternalPredicate));
         info->setVisibleName(caption().toUtf8().constData());
         reset_name = false;
     }
diff --git a/client.h b/client.h
index 5f5ac91583..8737ff5bf5 100644
--- a/client.h
+++ b/client.h
@@ -55,6 +55,19 @@ class TabBoxClientImpl;
 class Bridge;
 class PaintRedirector;
 
+
+/**
+ * @brief Defines Predicates on how to search for a Client.
+ *
+ * Used by Workspace::findClient.
+ */
+enum class Predicate {
+    WindowMatch,
+    WrapperIdMatch,
+    FrameIdMatch,
+    InputIdMatch
+};
+
 class Client
     : public Toplevel
 {
@@ -978,7 +991,6 @@ private:
     static bool check_active_modal; ///< \see Client::checkActiveModal()
     QKeySequence _shortcut;
     int sm_stacking_order;
-    friend struct FetchNameInternalPredicate;
     friend struct ResetupRulesProcedure;
     friend class GeometryUpdatesBlocker;
     PaintRedirector* paintRedirector;
@@ -1269,9 +1281,6 @@ inline void Client::print(T &stream) const
            << resourceName() << ";Caption:" << caption() << "\'";
 }
 
-KWIN_COMPARE_PREDICATE(WrapperIdMatchPredicate, Client, Window, cl->wrapperId() == value);
-KWIN_COMPARE_PREDICATE(InputIdMatchPredicate, Client, Window, cl->inputId() == value);
-
 } // namespace
 Q_DECLARE_METATYPE(KWin::Client*)
 Q_DECLARE_METATYPE(QList<KWin::Client*>)
diff --git a/effects.cpp b/effects.cpp
index 1d6f913449..b847a03911 100644
--- a/effects.cpp
+++ b/effects.cpp
@@ -1112,7 +1112,7 @@ WindowQuadType EffectsHandlerImpl::newWindowQuadType()
 
 EffectWindow* EffectsHandlerImpl::findWindow(WId id) const
 {
-    if (Client* w = Workspace::self()->findClient(WindowMatchPredicate(id)))
+    if (Client* w = Workspace::self()->findClient(Predicate::WindowMatch, id))
         return w->effectWindow();
     if (Unmanaged* w = Workspace::self()->findUnmanaged(id))
         return w->effectWindow();
diff --git a/events.cpp b/events.cpp
index 0005151401..07eae014a5 100644
--- a/events.cpp
+++ b/events.cpp
@@ -234,16 +234,16 @@ bool Workspace::workspaceEvent(xcb_generic_event_t *e)
 
     const xcb_window_t eventWindow = findEventWindow(e);
     if (eventWindow != XCB_WINDOW_NONE) {
-        if (Client* c = findClient(WindowMatchPredicate(eventWindow))) {
+        if (Client* c = findClient(Predicate::WindowMatch, eventWindow)) {
             if (c->windowEvent(e))
                 return true;
-        } else if (Client* c = findClient(WrapperIdMatchPredicate(eventWindow))) {
+        } else if (Client* c = findClient(Predicate::WrapperIdMatch, eventWindow)) {
             if (c->windowEvent(e))
                 return true;
-        } else if (Client* c = findClient(FrameIdMatchPredicate(eventWindow))) {
+        } else if (Client* c = findClient(Predicate::FrameIdMatch, eventWindow)) {
             if (c->windowEvent(e))
                 return true;
-        } else if (Client *c = findClient(InputIdMatchPredicate(eventWindow))) {
+        } else if (Client *c = findClient(Predicate::InputIdMatch, eventWindow)) {
             if (c->windowEvent(e))
                 return true;
         } else if (Unmanaged* c = findUnmanaged(eventWindow)) {
@@ -300,7 +300,7 @@ bool Workspace::workspaceEvent(xcb_generic_event_t *e)
         updateXTime();
 
         const auto *event = reinterpret_cast<xcb_map_request_event_t*>(e);
-        if (Client* c = findClient(WindowMatchPredicate(event->window))) {
+        if (Client* c = findClient(Predicate::WindowMatch, event->window)) {
             // e->xmaprequest.window is different from e->xany.window
             // TODO this shouldn't be necessary now
             c->windowEvent(e);
@@ -350,7 +350,7 @@ bool Workspace::workspaceEvent(xcb_generic_event_t *e)
             break;
         // TODO is this cliente ever found, given that client events are searched above?
         const auto *event = reinterpret_cast<xcb_leave_notify_event_t*>(e);
-        Client* c = findClient(FrameIdMatchPredicate(event->event));
+        Client* c = findClient(Predicate::FrameIdMatch, event->event);
         if (c && event->detail != XCB_NOTIFY_DETAIL_INFERIOR)
             QWhatsThis::leaveWhatsThisMode();
         break;
diff --git a/group.cpp b/group.cpp
index 296da16844..1819f928d1 100644
--- a/group.cpp
+++ b/group.cpp
@@ -203,7 +203,7 @@ Group::Group(Window leader_P)
         refcount(0)
 {
     if (leader_P != None) {
-        leader_client = workspace()->findClient(WindowMatchPredicate(leader_P));
+        leader_client = workspace()->findClient(Predicate::WindowMatch, leader_P);
         leader_info = new NETWinInfo(connection(), leader_P, rootWindow(),
                                       0, NET::WM2StartupId);
     }
@@ -583,7 +583,7 @@ void Client::setTransient(xcb_window_t new_transient_for_id)
         transient_for = NULL;
         m_transientForId = new_transient_for_id;
         if (m_transientForId != XCB_WINDOW_NONE && !groupTransient()) {
-            transient_for = workspace()->findClient(WindowMatchPredicate(m_transientForId));
+            transient_for = workspace()->findClient(Predicate::WindowMatch, m_transientForId);
             assert(transient_for != NULL);   // verifyTransient() had to check this
             transient_for->addTransient(this);
         } // checkGroup() will check 'check_active_modal'
@@ -755,14 +755,14 @@ xcb_window_t Client::verifyTransientFor(xcb_window_t new_transient_for, bool set
     xcb_window_t before_search = new_transient_for;
     while (new_transient_for != XCB_WINDOW_NONE
             && new_transient_for != rootWindow()
-            && !workspace()->findClient(WindowMatchPredicate(new_transient_for))) {
+            && !workspace()->findClient(Predicate::WindowMatch, new_transient_for)) {
         Xcb::Tree tree(new_transient_for);
         if (tree.isNull()) {
             break;
         }
         new_transient_for = tree->parent;
     }
-    if (Client* new_transient_for_client = workspace()->findClient(WindowMatchPredicate(new_transient_for))) {
+    if (Client* new_transient_for_client = workspace()->findClient(Predicate::WindowMatch, new_transient_for)) {
         if (new_transient_for != before_search) {
             qDebug() << "Client " << this << " has WM_TRANSIENT_FOR poiting to non-toplevel window "
                          << before_search << ", child of " << new_transient_for_client << ", adjusting." << endl;
@@ -776,7 +776,7 @@ xcb_window_t Client::verifyTransientFor(xcb_window_t new_transient_for, bool set
     int count = 20;
     xcb_window_t loop_pos = new_transient_for;
     while (loop_pos != XCB_WINDOW_NONE && loop_pos != rootWindow()) {
-        Client* pos = workspace()->findClient(WindowMatchPredicate(loop_pos));
+        Client* pos = workspace()->findClient(Predicate::WindowMatch, loop_pos);
         if (pos == NULL)
             break;
         loop_pos = pos->m_transientForId;
@@ -786,7 +786,7 @@ xcb_window_t Client::verifyTransientFor(xcb_window_t new_transient_for, bool set
         }
     }
     if (new_transient_for != rootWindow()
-            && workspace()->findClient(WindowMatchPredicate(new_transient_for)) == NULL) {
+            && workspace()->findClient(Predicate::WindowMatch, new_transient_for) == NULL) {
         // it's transient for a specific window, but that window is not mapped
         new_transient_for = rootWindow();
     }
diff --git a/killwindow.cpp b/killwindow.cpp
index f12cab9c92..d3d951c3bc 100644
--- a/killwindow.cpp
+++ b/killwindow.cpp
@@ -203,7 +203,7 @@ void KillWindow::killWindowId(xcb_window_t window_to_kill)
     xcb_window_t window = window_to_kill;
     Client* client = NULL;
     while (true) {
-        client = Workspace::self()->findClient(FrameIdMatchPredicate(window));
+        client = Workspace::self()->findClient(Predicate::FrameIdMatch, window);
         if (client) {
             break; // Found the client
         }
diff --git a/layers.cpp b/layers.cpp
index 5dd8a4a5c8..362839a239 100644
--- a/layers.cpp
+++ b/layers.cpp
@@ -694,7 +694,7 @@ void Client::restackWindow(xcb_window_t above, int detail, NET::RequestSource sr
 {
     Client *other = 0;
     if (detail == XCB_STACK_MODE_OPPOSITE) {
-        other = workspace()->findClient(WindowMatchPredicate(above));
+        other = workspace()->findClient(Predicate::WindowMatch, above);
         if (!other) {
             workspace()->raiseOrLowerClient(this);
             return;
@@ -713,20 +713,20 @@ void Client::restackWindow(xcb_window_t above, int detail, NET::RequestSource sr
         }
     }
     else if (detail == XCB_STACK_MODE_TOP_IF) {
-        other = workspace()->findClient(WindowMatchPredicate(above));
+        other = workspace()->findClient(Predicate::WindowMatch, above);
         if (other && other->geometry().intersects(geometry()))
             workspace()->raiseClientRequest(this, src, timestamp);
         return;
     }
     else if (detail == XCB_STACK_MODE_BOTTOM_IF) {
-        other = workspace()->findClient(WindowMatchPredicate(above));
+        other = workspace()->findClient(Predicate::WindowMatch, above);
         if (other && other->geometry().intersects(geometry()))
             workspace()->lowerClientRequest(this, src, timestamp);
         return;
     }
 
     if (!other)
-        other = workspace()->findClient(WindowMatchPredicate(above));
+        other = workspace()->findClient(Predicate::WindowMatch, above);
 
     if (other && detail == XCB_STACK_MODE_ABOVE) {
         ToplevelList::const_iterator  it = workspace()->stackingOrder().constEnd(),
diff --git a/netinfo.cpp b/netinfo.cpp
index 391ffb3956..85983b478b 100644
--- a/netinfo.cpp
+++ b/netinfo.cpp
@@ -157,7 +157,7 @@ void RootInfo::changeCurrentDesktop(int d)
 void RootInfo::changeActiveWindow(xcb_window_t w, NET::RequestSource src, xcb_timestamp_t timestamp, xcb_window_t active_window)
 {
     Workspace *workspace = Workspace::self();
-    if (Client* c = workspace->findClient(WindowMatchPredicate(w))) {
+    if (Client* c = workspace->findClient(Predicate::WindowMatch, w)) {
         if (timestamp == CurrentTime)
             timestamp = c->userTime();
         if (src != NET::FromApplication && src != FromTool)
@@ -172,7 +172,7 @@ void RootInfo::changeActiveWindow(xcb_window_t w, NET::RequestSource src, xcb_ti
                 workspace->activateClient(c);
             // if activation of the requestor's window would be allowed, allow activation too
             else if (active_window != None
-                    && (c2 = workspace->findClient(WindowMatchPredicate(active_window))) != NULL
+                    && (c2 = workspace->findClient(Predicate::WindowMatch, active_window)) != NULL
                     && workspace->allowClientActivation(c2,
                             timestampCompare(timestamp, c2->userTime() > 0 ? timestamp : c2->userTime()), false, true)) {
                 workspace->activateClient(c);
@@ -184,7 +184,7 @@ void RootInfo::changeActiveWindow(xcb_window_t w, NET::RequestSource src, xcb_ti
 
 void RootInfo::restackWindow(xcb_window_t w, RequestSource src, xcb_window_t above, int detail, xcb_timestamp_t timestamp)
 {
-    if (Client* c = Workspace::self()->findClient(WindowMatchPredicate(w))) {
+    if (Client* c = Workspace::self()->findClient(Predicate::WindowMatch, w)) {
         if (timestamp == CurrentTime)
             timestamp = c->userTime();
         if (src != NET::FromApplication && src != FromTool)
@@ -195,14 +195,14 @@ void RootInfo::restackWindow(xcb_window_t w, RequestSource src, xcb_window_t abo
 
 void RootInfo::closeWindow(xcb_window_t w)
 {
-    Client* c = Workspace::self()->findClient(WindowMatchPredicate(w));
+    Client* c = Workspace::self()->findClient(Predicate::WindowMatch, w);
     if (c)
         c->closeWindow();
 }
 
 void RootInfo::moveResize(xcb_window_t w, int x_root, int y_root, unsigned long direction)
 {
-    Client* c = Workspace::self()->findClient(WindowMatchPredicate(w));
+    Client* c = Workspace::self()->findClient(Predicate::WindowMatch, w);
     if (c) {
         updateXTime(); // otherwise grabbing may have old timestamp - this message should include timestamp
         c->NETMoveResize(x_root, y_root, (Direction)direction);
@@ -211,14 +211,14 @@ void RootInfo::moveResize(xcb_window_t w, int x_root, int y_root, unsigned long
 
 void RootInfo::moveResizeWindow(xcb_window_t w, int flags, int x, int y, int width, int height)
 {
-    Client* c = Workspace::self()->findClient(WindowMatchPredicate(w));
+    Client* c = Workspace::self()->findClient(Predicate::WindowMatch, w);
     if (c)
         c->NETMoveResizeWindow(flags, x, y, width, height);
 }
 
 void RootInfo::gotPing(xcb_window_t w, xcb_timestamp_t timestamp)
 {
-    if (Client* c = Workspace::self()->findClient(WindowMatchPredicate(w)))
+    if (Client* c = Workspace::self()->findClient(Predicate::WindowMatch, w))
         c->gotPing(timestamp);
 }
 
diff --git a/scripting/workspace_wrapper.cpp b/scripting/workspace_wrapper.cpp
index d42222543f..cb52a828bd 100644
--- a/scripting/workspace_wrapper.cpp
+++ b/scripting/workspace_wrapper.cpp
@@ -261,7 +261,7 @@ void WorkspaceWrapper::hideOutline()
 
 Client *WorkspaceWrapper::getClient(qulonglong windowId)
 {
-    return Workspace::self()->findClient(WindowMatchPredicate(windowId));
+    return Workspace::self()->findClient(Predicate::WindowMatch, windowId);
 }
 
 QSize WorkspaceWrapper::desktopGridSize() const
diff --git a/thumbnailitem.cpp b/thumbnailitem.cpp
index 531dfe8802..d4124ae14b 100644
--- a/thumbnailitem.cpp
+++ b/thumbnailitem.cpp
@@ -138,7 +138,7 @@ void WindowThumbnailItem::setWId(qulonglong wId)
     }
     m_wId = wId;
     if (m_wId != 0) {
-        setClient(Workspace::self()->findClient(WindowMatchPredicate(m_wId)));
+        setClient(Workspace::self()->findClient(Predicate::WindowMatch, m_wId));
     } else if (m_client) {
         m_client = NULL;
         emit clientChanged();
@@ -165,7 +165,7 @@ void WindowThumbnailItem::paint(QPainter *painter)
     if (effects) {
         return;
     }
-    Client *client = Workspace::self()->findClient(WindowMatchPredicate(m_wId));
+    Client *client = Workspace::self()->findClient(Predicate::WindowMatch, m_wId);
     if (!client) {
         return;
     }
diff --git a/toplevel.h b/toplevel.h
index 70775e538b..f8a05bead8 100644
--- a/toplevel.h
+++ b/toplevel.h
@@ -685,9 +685,6 @@ inline T *Toplevel::findInList(const QList<T*> &list, std::function<bool (const
 QDebug& operator<<(QDebug& stream, const Toplevel*);
 QDebug& operator<<(QDebug& stream, const ToplevelList&);
 
-KWIN_COMPARE_PREDICATE(WindowMatchPredicate, Toplevel, Window, cl->window() == value);
-KWIN_COMPARE_PREDICATE(FrameIdMatchPredicate, Toplevel, Window, cl->frameId() == value);
-
 } // namespace
 Q_DECLARE_METATYPE(KWin::Toplevel*)
 
diff --git a/utils.h b/utils.h
index 9deae736c3..99291d64ff 100644
--- a/utils.h
+++ b/utils.h
@@ -156,40 +156,6 @@ public:
 #define UrgencyHint XUrgencyHint
 #endif
 
-// for STL-like algo's
-#define KWIN_CHECK_PREDICATE( name, cls, check ) \
-    struct name \
-    { \
-        inline bool operator()( const cls* cl ) { return check; } \
-    }
-
-#define KWIN_COMPARE_PREDICATE( name, cls, type, check ) \
-    struct name \
-    { \
-        typedef type type_helper; /* in order to work also with type being 'const Client*' etc. */ \
-        inline name( const type_helper& compare_value ) : value( compare_value ) {} \
-        inline bool operator()( const cls* cl ) { return check; } \
-        const type_helper& value; \
-    }
-
-#define KWIN_PROCEDURE( name, cls, action ) \
-    struct name \
-    { \
-        inline void operator()( cls* cl ) { action; } \
-    }
-
-KWIN_CHECK_PREDICATE(TruePredicate, Client, cl == cl /*true, avoid warning about 'cl' */);
-
-template< typename T >
-Client* findClientInList(const ClientList& list, T predicate)
-{
-    for (ClientList::ConstIterator it = list.begin(); it != list.end(); ++it) {
-        if (predicate(const_cast< const Client* >(*it)))
-            return *it;
-    }
-    return NULL;
-}
-
 QPoint cursorPos();
 
 // converting between X11 mouse/keyboard state mask and Qt button/keyboard states
diff --git a/workspace.cpp b/workspace.cpp
index 50df1d6cd2..3d2c672752 100644
--- a/workspace.cpp
+++ b/workspace.cpp
@@ -381,7 +381,7 @@ void Workspace::init()
     Client* new_active_client = NULL;
     if (!qApp->isSessionRestored()) {
         --block_focus;
-        new_active_client = findClient(WindowMatchPredicate(client_info.activeWindow()));
+        new_active_client = findClient(Predicate::WindowMatch, client_info.activeWindow());
     }
     if (new_active_client == NULL
             && activeClient() == NULL && should_get_focus.count() == 0) {
@@ -1527,6 +1527,17 @@ void Workspace::slotToggleCompositing()
     }
 }
 
+Client *Workspace::findClient(std::function<bool (const Client*)> func) const
+{
+    if (Client *ret = Toplevel::findInList(clients, func)) {
+        return ret;
+    }
+    if (Client *ret = Toplevel::findInList(desktops, func)) {
+        return ret;
+    }
+    return nullptr;
+}
+
 Unmanaged *Workspace::findUnmanaged(std::function<bool (const Unmanaged*)> func) const
 {
     return Toplevel::findInList(unmanaged, func);
@@ -1539,6 +1550,29 @@ Unmanaged *Workspace::findUnmanaged(xcb_window_t w) const
     });
 }
 
+Client *Workspace::findClient(Predicate predicate, xcb_window_t w) const
+{
+    switch (predicate) {
+    case Predicate::WindowMatch:
+        return findClient([w](const Client *c) {
+            return c->window() == w;
+        });
+    case Predicate::WrapperIdMatch:
+        return findClient([w](const Client *c) {
+            return c->wrapperId() == w;
+        });
+    case Predicate::FrameIdMatch:
+        return findClient([w](const Client *c) {
+            return c->frameId() == w;
+        });
+    case Predicate::InputIdMatch:
+        return findClient([w](const Client *c) {
+            return c->inputId() == w;
+        });
+    }
+    return nullptr;
+}
+
 } // namespace
 
 #include "workspace.moc"
diff --git a/workspace.h b/workspace.h
index f3ef7b9e73..71c328e4f4 100644
--- a/workspace.h
+++ b/workspace.h
@@ -55,6 +55,7 @@ class KillWindow;
 class ShortcutDialog;
 class UserActionsMenu;
 class Compositor;
+enum class Predicate;
 
 class Workspace : public QObject, public KDecorationDefines
 {
@@ -72,7 +73,44 @@ public:
 
     bool hasClient(const Client*);
 
-    template<typename T> Client* findClient(T predicate) const;
+    /**
+     * @brief Finds the first Client matching the condition expressed by passed in @p func.
+     *
+     * Internally findClient uses the std::find_if algorithm and that determines how the function
+     * needs to be implemented. An example usage for finding a Client with a matching windowId
+     * @code
+     * xcb_window_t w; // our test window
+     * Client *client = findClient([w](const Client *c) -> bool {
+     *     return c->window() == w;
+     * });
+     * @endcode
+     *
+     * For the standard cases of matching the window id with one of the Client's windows use
+     * the simplified overload method findClient(Predicate, xcb_window_t). Above example
+     * can be simplified to:
+     * @code
+     * xcb_window_t w; // our test window
+     * Client *client = findClient(Predicate::WindowMatch, w);
+     * @endcode
+     *
+     * @param func Unary function that accepts a Client* as argument and
+     * returns a value convertible to bool. The value returned indicates whether the
+     * Client* is considered a match in the context of this function.
+     * The function shall not modify its argument.
+     * This can either be a function pointer or a function object.
+     * @return KWin::Client* The found Client or @c null
+     * @see findClient(Predicate, xcb_window_t)
+     */
+    Client *findClient(std::function<bool (const Client*)> func) const;
+    /**
+     * @brief Finds the Client matching the given match @p predicate for the given window.
+     *
+     * @param predicate Which window should be compared
+     * @param w The window id to test against
+     * @return KWin::Client* The found Client or @c null
+     * @see findClient(std::function<bool (const Client*)>)
+     */
+    Client *findClient(Predicate predicate, xcb_window_t w) const;
     void forEachClient(std::function<void (Client*)> func);
     Unmanaged *findUnmanaged(std::function<bool (const Unmanaged*)> func) const;
     /**
@@ -659,17 +697,6 @@ inline QPoint Workspace::focusMousePosition() const
     return focusMousePos;
 }
 
-template< typename T >
-inline Client* Workspace::findClient(T predicate) const
-{
-    if (Client* ret = findClientInList(clients, predicate))
-        return ret;
-    if (Client* ret = findClientInList(desktops, predicate))
-        return ret;
-    return NULL;
-}
-
-
 inline
 void Workspace::forEachClient(std::function< void (Client*) > func)
 {
@@ -683,11 +710,11 @@ void Workspace::forEachUnmanaged(std::function< void (Unmanaged*) > func)
     std::for_each(unmanaged.constBegin(), unmanaged.constEnd(), func);
 }
 
-KWIN_COMPARE_PREDICATE(ClientMatchPredicate, Client, const Client*, cl == value);
-
 inline bool Workspace::hasClient(const Client* c)
 {
-    return findClient(ClientMatchPredicate(c));
+    return findClient([c](const Client *test) {
+        return test == c;
+    });
 }
 
 inline Workspace *workspace()