On branch main

modified:   src/ch08.md
new file:   src/ex-ch08-01.zig

src/ch08.md

@@ -357,3 +357,37 @@ ptr_info.Pointer.child.writeAll(self, data);
 
 ## Использование маркированных объединений
 
+...
+
+Вот рабочий полноценный пример:
+
+```zig
+const std = @import("std");
+const os = std.os;
+
+const Writer = union(enum) {
+  file: File,
+
+  fn writeAll(self: Writer, data: []const u8) !void {
+    switch (self) {
+      .file => |file| return file.writeAll(data),
+    }
+  }
+};
+
+const File = struct {
+  fd: os.fd_t,
+
+  fn writeAll(self: File, data: []const u8) !void {
+    _ = try std.os.write(self.fd, data);
+  }
+};
+
+
+pub fn main() !void {
+  const file = File{.fd = std.io.getStdOut().handle};
+  const writer = Writer{.file = file};
+  try writer.writeAll("hi\n");
+}
+
+```

src/ex-ch08-01.zig

@@ -0,0 +1,28 @@
+
+const std = @import("std");
+const os = std.os;
+
+const Writer = union(enum) {
+  file: File,
+
+  fn writeAll(self: Writer, data: []const u8) !void {
+    switch (self) {
+      .file => |file| return file.writeAll(data),
+    }
+  }
+};
+
+const File = struct {
+  fd: os.fd_t,
+
+  fn writeAll(self: File, data: []const u8) !void {
+    _ = try std.os.write(self.fd, data);
+  }
+};
+
+
+pub fn main() !void {
+  const file = File{.fd = std.io.getStdOut().handle};
+  const writer = Writer{.file = file};
+  try writer.writeAll("hi\n");
+}