mod: each layout and widget now allocates their own instance in memory using the provided allocator (and destroy's themselfes in the end)

src/layout/Margin.zig

@@ -26,6 +26,7 @@ pub fn Layout(comptime Event: type, comptime Element: type, comptime Renderer: t
     }
     const Events = std.ArrayList(Event);
     return struct {
+        allocator: std.mem.Allocator = undefined,
         size: terminal.Size = undefined,
         require_render: bool = false,
         element: Element = undefined,
@@ -40,18 +41,19 @@ pub fn Layout(comptime Event: type, comptime Element: type, comptime Renderer: t
             bottom: u8 = 0,
         };
 
-        pub fn init(allocator: std.mem.Allocator, config: Config, element: Element) @This() {
+        pub fn init(allocator: std.mem.Allocator, config: Config, element: Element) *@This() {
             if (config.margin) |margin| {
                 std.debug.assert(margin <= 50);
             } else {
                 std.debug.assert(config.left + config.right < 100);
                 std.debug.assert(config.top + config.bottom < 100);
             }
-            return .{
-                .config = config,
-                .element = element,
-                .events = Events.init(allocator),
-            };
+            const layout = allocator.create(@This()) catch @panic("OOM");
+            layout.allocator = allocator;
+            layout.config = config;
+            layout.element = element;
+            layout.events = Events.init(allocator);
+            return layout;
         }
 
         pub fn deinit(this: *@This()) void {
@@ -64,6 +66,8 @@ pub fn Layout(comptime Event: type, comptime Element: type, comptime Renderer: t
                     widget.deinit();
                 },
             }
+            this.allocator.destroy(this);
+            this.* = undefined;
         }
 
         pub fn handle(this: *@This(), event: Event) !*Events {