Add ViewEngine for easy server integration

- ViewEngine manages views directory with path resolution
- Auto-loads mixins from views/mixins/ directory
- Simplifies template paths (relative to views dir, auto-adds extension)
- Updated example app to use ViewEngine
- Added example mixins (buttons.pug, cards.pug)
- Updated CLAUDE.md with ViewEngine documentation

src/examples/app_01/main.zig

@@ -1,7 +1,7 @@
 //! Pugz Template Inheritance Demo
 //!
 //! A web application demonstrating Pug-style template inheritance
-//! using the Pugz template engine with http.zig server.
+//! using the Pugz ViewEngine with http.zig server.
 //!
 //! Routes:
 //!   GET /           - Home page (layout.pug)
@@ -19,58 +19,25 @@ const Allocator = std.mem.Allocator;
 /// Application state shared across all requests
 const App = struct {
     allocator: Allocator,
-    views_dir: []const u8,
+    engine: pugz.ViewEngine,
 
-    /// File resolver for loading templates from disk
-    pub fn fileResolver(allocator: Allocator, path: []const u8) ?[]const u8 {
-        const file = std.fs.cwd().openFile(path, .{}) catch return null;
-        defer file.close();
-        return file.readToEndAlloc(allocator, 1024 * 1024) catch null;
+    pub fn init(allocator: Allocator) !App {
+        return .{
+            .allocator = allocator,
+            .engine = try pugz.ViewEngine.init(allocator, .{
+                .views_dir = "src/examples/app_01/views",
+            }),
+        };
     }
 
-    /// Render a template with data
-    pub fn render(self: *App, template_name: []const u8, data: anytype) ![]u8 {
-        // Build full path
-        const template_path = try std.fs.path.join(self.allocator, &.{ self.views_dir, template_name });
-        defer self.allocator.free(template_path);
-
-        // Load template source
-        const source = fileResolver(self.allocator, template_path) orelse {
-            return error.TemplateNotFound;
-        };
-        defer self.allocator.free(source);
-
-        // Parse template
-        var lexer = pugz.Lexer.init(self.allocator, source);
-        const tokens = try lexer.tokenize();
-
-        var parser = pugz.Parser.init(self.allocator, tokens);
-        const doc = try parser.parse();
-
-        // Setup context with data
-        var ctx = pugz.runtime.Context.init(self.allocator);
-        defer ctx.deinit();
-
-        try ctx.pushScope();
-        inline for (std.meta.fields(@TypeOf(data))) |field| {
-            const value = @field(data, field.name);
-            try ctx.set(field.name, pugz.runtime.toValue(self.allocator, value));
-        }
-
-        // Render with file resolver for includes/extends
-        var runtime = pugz.runtime.Runtime.init(self.allocator, &ctx, .{
-            .file_resolver = fileResolver,
-            .base_dir = self.views_dir,
-        });
-        defer runtime.deinit();
-
-        return runtime.renderOwned(doc);
+    pub fn deinit(self: *App) void {
+        self.engine.deinit();
     }
 };
 
 /// Handler for GET /
 fn index(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
-    const html = app.render("layout.pug", .{
+    const html = app.engine.render(app.allocator, "layout", .{
         .title = "Home",
     }) catch |err| {
         res.status = 500;
@@ -84,7 +51,7 @@ fn index(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
 
 /// Handler for GET /page-a - demonstrates extends and block override
 fn pageA(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
-    const html = app.render("page-a.pug", .{
+    const html = app.engine.render(app.allocator, "page-a", .{
         .title = "Page A - Pets",
         .items = &[_][]const u8{ "A", "B", "C" },
         .n = 0,
@@ -100,7 +67,7 @@ fn pageA(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
 
 /// Handler for GET /page-b - demonstrates sub-layout inheritance
 fn pageB(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
-    const html = app.render("page-b.pug", .{
+    const html = app.engine.render(app.allocator, "page-b", .{
         .title = "Page B - Sub Layout",
     }) catch |err| {
         res.status = 500;
@@ -114,7 +81,7 @@ fn pageB(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
 
 /// Handler for GET /append - demonstrates block append
 fn pageAppend(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
-    const html = app.render("page-append.pug", .{
+    const html = app.engine.render(app.allocator, "page-append", .{
         .title = "Page Append",
     }) catch |err| {
         res.status = 500;
@@ -128,7 +95,7 @@ fn pageAppend(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
 
 /// Handler for GET /append-opt - demonstrates optional block keyword
 fn pageAppendOptional(app: *App, _: *httpz.Request, res: *httpz.Response) !void {
-    const html = app.render("page-appen-optional-blk.pug", .{
+    const html = app.engine.render(app.allocator, "page-appen-optional-blk", .{
         .title = "Page Append Optional",
     }) catch |err| {
         res.status = 500;
@@ -145,13 +112,9 @@ pub fn main() !void {
     defer _ = gpa.deinit();
     const allocator = gpa.allocator();
 
-    // Views directory - relative to current working directory
-    const views_dir = "src/examples/app_01/views";
-
-    var app = App{
-        .allocator = allocator,
-        .views_dir = views_dir,
-    };
+    // 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);
     defer server.deinit();

src/examples/app_01/views/mixins/buttons.pug

@@ -0,0 +1,5 @@
+mixin btn(text, type="primary")
+  button(class="btn btn-" + type)= text
+
+mixin btn-link(href, text)
+  a.btn.btn-link(href=href)= text

src/examples/app_01/views/mixins/cards.pug

@@ -0,0 +1,11 @@
+mixin card(title)
+  .card
+    .card-header
+      h3= title
+    .card-body
+      block
+
+mixin card-simple(title, body)
+  .card
+    h3= title
+    p= body