Fix infinite loop in lexer when parsing attribute expressions with operators

The lexer would hang when encountering operators like + in attribute values
(e.g., class="btn btn-" + type). Added scanAttrValuePart to handle
expression continuation with operators (+, -, *, /).

Also cleaned up debug prints from view_engine.zig and demo/main.zig.

src/examples/demo/main.zig

@@ -19,104 +19,34 @@ const Allocator = std.mem.Allocator;
 /// Application state shared across all requests
 const App = struct {
     allocator: Allocator,
-    engine: pugz.ViewEngine,
+    view: pugz.ViewEngine,
 
     pub fn init(allocator: Allocator) !App {
         return .{
             .allocator = allocator,
-            .engine = try pugz.ViewEngine.init(allocator, .{
-                .views_dir = "src/examples/app_01/views",
+            .view = try pugz.ViewEngine.init(allocator, .{
+                .views_dir = "src/examples/demo/views",
             }),
         };
     }
 
     pub fn deinit(self: *App) void {
-        self.engine.deinit();
+        self.view.deinit();
     }
 };
 
-/// Handler for GET /
-fn index(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
-    const html = app.engine.render(app.allocator, "layout", .{
-        .title = "Home",
-    }) catch |err| {
-        res.status = 500;
-        res.body = @errorName(err);
-        return;
-    };
-
-    res.content_type = .HTML;
-    res.body = html;
-}
-
-/// Handler for GET /page-a - demonstrates extends and block override
-fn pageA(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
-    const html = app.engine.render(app.allocator, "page-a", .{
-        .title = "Page A - Pets",
-        .items = &[_][]const u8{ "A", "B", "C" },
-        .n = 0,
-    }) catch |err| {
-        res.status = 500;
-        res.body = @errorName(err);
-        return;
-    };
-
-    res.content_type = .HTML;
-    res.body = html;
-}
-
-/// Handler for GET /page-b - demonstrates sub-layout inheritance
-fn pageB(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
-    const html = app.engine.render(app.allocator, "page-b", .{
-        .title = "Page B - Sub Layout",
-    }) catch |err| {
-        res.status = 500;
-        res.body = @errorName(err);
-        return;
-    };
-
-    res.content_type = .HTML;
-    res.body = html;
-}
-
-/// Handler for GET /append - demonstrates block append
-fn pageAppend(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
-    const html = app.engine.render(app.allocator, "page-append", .{
-        .title = "Page Append",
-    }) catch |err| {
-        res.status = 500;
-        res.body = @errorName(err);
-        return;
-    };
-
-    res.content_type = .HTML;
-    res.body = html;
-}
-
-/// Handler for GET /append-opt - demonstrates optional block keyword
-fn pageAppendOptional(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
-    const html = app.engine.render(app.allocator, "page-appen-optional-blk", .{
-        .title = "Page Append Optional",
-    }) catch |err| {
-        res.status = 500;
-        res.body = @errorName(err);
-        return;
-    };
-
-    res.content_type = .HTML;
-    res.body = html;
-}
-
 pub fn main() !void {
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
-    defer _ = gpa.deinit();
+    defer if (gpa.deinit() == .leak) @panic("leak");
+
     const allocator = gpa.allocator();
 
     // Initialize view engine once at startup
     var app = try App.init(allocator);
     defer app.deinit();
 
-    var server = try httpz.Server(*App).init(allocator, .{ .port = 8080 }, &app);
+    const port = 8080;
+    var server = try httpz.Server(*App).init(allocator, .{ .port = port }, &app);
     defer server.deinit();
 
     var router = try server.router(.{});
@@ -132,7 +62,7 @@ pub fn main() !void {
         \\
         \\Pugz Template Inheritance Demo
         \\==============================
-        \\Server running at http://localhost:8080
+        \\Server running at http://localhost:{d}
         \\
         \\Routes:
         \\  GET /           - Home page (base layout)
@@ -143,7 +73,79 @@ pub fn main() !void {
         \\
         \\Press Ctrl+C to stop.
         \\
-    , .{});
+    , .{port});
 
     try server.listen();
 }
+
+/// Handler for GET /
+fn index(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
+    const html = app.view.render(app.allocator, "layout", .{
+        .title = "Home",
+    }) catch |err| {
+        res.status = 500;
+        res.body = @errorName(err);
+        return;
+    };
+
+    res.content_type = .HTML;
+    res.body = html;
+}
+
+/// Handler for GET /page-a - demonstrates extends and block override
+fn pageA(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
+    const html = app.view.render(app.allocator, "page-a", .{
+        .title = "Page A - Pets",
+        .items = &[_][]const u8{ "A", "B", "C" },
+        .n = 0,
+    }) catch |err| {
+        res.status = 500;
+        res.body = @errorName(err);
+        return;
+    };
+
+    res.content_type = .HTML;
+    res.body = html;
+}
+
+/// Handler for GET /page-b - demonstrates sub-layout inheritance
+fn pageB(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
+    const html = app.view.render(app.allocator, "page-b", .{
+        .title = "Page B - Sub Layout",
+    }) catch |err| {
+        res.status = 500;
+        res.body = @errorName(err);
+        return;
+    };
+
+    res.content_type = .HTML;
+    res.body = html;
+}
+
+/// Handler for GET /append - demonstrates block append
+fn pageAppend(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
+    const html = app.view.render(app.allocator, "page-append", .{
+        .title = "Page Append",
+    }) catch |err| {
+        res.status = 500;
+        res.body = @errorName(err);
+        return;
+    };
+
+    res.content_type = .HTML;
+    res.body = html;
+}
+
+/// Handler for GET /append-opt - demonstrates optional block keyword
+fn pageAppendOptional(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
+    const html = app.view.render(app.allocator, "page-appen-optional-blk", .{
+        .title = "Page Append Optional",
+    }) catch |err| {
+        res.status = 500;
+        res.body = @errorName(err);
+        return;
+    };
+
+    res.content_type = .HTML;
+    res.body = html;
+}