examples: keybinding for cycling workspace settings (among "unbound" and current)

Only relevant when using dynamic workspace. Typically used to change the empty
workspace settings to the one you want.

examples/keybindings.js

@@ -33,7 +33,6 @@ function gotoByIndex() {
     }
 }
 
-
 function windowMarks() {
     const Meta = imports.gi.Meta;
     var marks = {}
@@ -77,7 +76,6 @@ function windowMarks() {
     }
 }
 
-
 function swapNeighbours(binding = "<Super>y") {
     var Tiling = Extension.imports.tiling;
     var Meta = imports.gi.Meta;
@@ -107,6 +105,67 @@ function cycleMonitor(binding = "<Super>d") {
     });
 }
 
+/**
+   Cycle the workspace settings bound to the current workspace.
+   (among the unused settings)
+   NB: Only relevant when using dynamic workspaces.
+ */
+function cycleWorkspaceSettings(binding = "<Super>q") {
+    var Tiling = Extension.imports.tiling;
+    var Settings = Extension.imports.settings;
+    var Utils = Extension.imports.utils;
+
+    function rotated(list, dir=1) {
+        return [].concat(
+            list.slice(dir),
+            list.slice(0, dir)
+        );
+    }
+
+    function cycle(mw, dir=1) {
+        let n = global.workspace_manager.get_n_workspaces();
+        let N = Settings.workspaceList.get_strv('list').length;
+        let space = Tiling.spaces.selectedSpace;
+        let wsI = space.workspace.index();
+
+        // 2 6 7 8   <-- indices
+        // x a b c   <-- settings
+        // a b c x   <-- rotated settings
+
+        let uuids = Settings.workspaceList.get_strv('list');
+        // Work on tuples of [uuid, settings] since we need to uuid association
+        // in the last step
+        let settings = uuids.map(
+            uuid => [uuid, Settings.getWorkspaceSettingsByUUID(uuid)]
+        );
+        settings.sort((a, b) => a[1].get_int('index') - b[1].get_int('index'));
+
+        let unbound = settings.slice(n);
+        let strip = [settings[wsI]].concat(unbound);
+
+        strip = rotated(strip, dir);
+
+        let nextSettings = strip[0];
+        unbound = strip.slice(1);
+
+        nextSettings[1].set_int('index', wsI);
+        space.setSettings(nextSettings); // ASSUMPTION: ok that two settings have same index here
+
+        // Re-assign unbound indices:
+        for (let i = n; i < N; i++) {
+            unbound[i-n][1].set_int('index', i);
+        }
+    }
+
+    Keybindings.bindkey(
+        binding, "next-space-setting",
+        mw => cycle(mw, -1), { activeInNavigator: true }
+    );
+    Keybindings.bindkey(
+        "<Shift>"+binding, "prev-space-setting",
+        mw => cycle(mw,  1), { activeInNavigator: true }
+    );
+}
 
 function showNavigator(binding = "<Super>j") {
     Keybindings.bindkey(binding, "show-minimap", () => null, { opensMinimap: true })