feat(content): parse document preemble

Show title stored in preemble of markdown file if available.

doc/blog.md

@@ -1,5 +1,7 @@
-# Blog
-
+---
+title: Welcome to my Blog
+date: 2025-11-01
+---
 This is the main entry page for my blog. I plan on writing on things I feel like worth sharing, mentioning for other developers, tinkers like me.
 
 The blog is currently a work in progress and will be updated once a first version of the tui website supports more dynamic contents.

src/content.zig

@@ -52,8 +52,14 @@ pub fn Content(App: type) type {
         fn handle(ctx: *anyopaque, model: *App.Model, event: App.Event) !void {
             const this: *@This() = @ptrCast(@alignCast(ctx));
             switch (event) {
-                .about => model.page = .about,
-                .blog => model.page = .blog,
+                .about => {
+                    model.page = .about;
+                    model.document = .init(@embedFile("about"));
+                },
+                .blog => {
+                    model.page = .blog;
+                    model.document = .init(@embedFile("blog"));
+                },
                 else => {},
             }
             this.page = model.page;
@@ -63,10 +69,7 @@ pub fn Content(App: type) type {
             _ = ctx;
             assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
-            const text = switch (model.page) {
-                .about => @embedFile("about"),
-                .blog => @embedFile("blog"),
-            };
+            const text = model.document.content;
             var index: usize = 0;
 
             for (0..size.y) |row| {
@@ -89,12 +92,8 @@ pub fn Content(App: type) type {
 
 pub fn Title(App: type) type {
     return struct {
-        text: []const u8,
-
         pub fn init() @This() {
-            return .{
-                .text = "<Title>",
-            };
+            return .{};
         }
 
         pub fn element(this: *@This()) App.Element {
@@ -106,16 +105,20 @@ pub fn Title(App: type) type {
             };
         }
 
-        fn content(ctx: *anyopaque, _: *const App.Model, cells: []zterm.Cell, size: zterm.Point) !void {
+        fn content(ctx: *anyopaque, model: *const App.Model, cells: []zterm.Cell, size: zterm.Point) !void {
             const this: *const @This() = @ptrCast(@alignCast(ctx));
+            _ = this;
             assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
-            for (0.., this.text) |idx, cp| {
-                cells[idx].style.fg = .green;
-                cells[idx].style.emphasis = &.{.bold};
-                cells[idx].cp = cp;
 
-                // NOTE do not write over the contents of this `Container`'s `Size`
-                if (idx == cells.len - 1) break;
+            if (model.document.title) |text| {
+                for (0.., text) |idx, cp| {
+                    cells[idx].style.fg = .green;
+                    cells[idx].style.emphasis = &.{.bold};
+                    cells[idx].cp = cp;
+
+                    // NOTE do not write over the contents of this `Container`'s `Size`
+                    if (idx == cells.len - 1) break;
+                }
             }
         }
     };

src/main.zig

@@ -6,7 +6,9 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(.{
+        .document = .init(@embedFile("blog")),
+    });
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -18,6 +20,8 @@ pub fn main() !void {
         },
     }, .{});
     defer container.deinit();
+    var content_container: App.Container = undefined;
+    defer content_container.deinit();
 
     // header with navigation buttons and content's title
     {
@@ -60,7 +64,7 @@ pub fn main() !void {
     // main actual tui_website page content
     {
         var content: Content = .init(allocator);
-        const content_container: App.Container = try .init(allocator, .{}, content.element());
+        content_container = try .init(allocator, .{}, content.element());
 
         var scrollable: App.Scrollable = .init(content_container, .enabled(.green));
         // intermediate container for *padding* containing the scrollable `Content`

src/model.zig

@@ -1,6 +1,48 @@
 page: Pages = .blog,
+document: Document = undefined,
 
 pub const Pages = enum {
     about,
     blog,
 };
+
+pub const Document = struct {
+    // preemble:
+    title: ?[]const u8 = null,
+    date: ?[]const u8 = null,
+    content: []const u8,
+
+    pub fn init(content: []const u8) @This() {
+        if (std.mem.startsWith(u8, content, "---\n")) {
+            var document: @This() = .{ .content = undefined };
+            // we assume the content includes a preemble
+            var iter = std.mem.splitSequence(u8, content, "---\n");
+            assert(iter.next().?.len == 0);
+            if (iter.next()) |preemble| {
+                var lines = std.mem.splitScalar(u8, preemble, '\n');
+                while (lines.next()) |line| {
+                    var entry = std.mem.splitSequence(u8, line, ": ");
+                    const key = entry.next().?;
+                    const value = entry.next();
+                    assert(entry.next() == null);
+                    if (std.meta.stringToEnum(Preemble, key)) |k| switch (k) {
+                        .title => document.title = value,
+                        .date => document.date = value,
+                    };
+                }
+            }
+            document.content = iter.next().?;
+            return document;
+        } else return .{
+            .content = content,
+        };
+    }
+};
+
+const Preemble = enum {
+    title,
+    date,
+};
+
+const std = @import("std");
+const assert = std.debug.assert;