Added another pointer example (#277)

docs/examples/pointer-example-3.js

@@ -0,0 +1,26 @@
+import { printDirectoryTree } from './pointer-example-3.zig';
+
+printDirectoryTree({
+    name: 'root',
+    entries: [
+        { file: { name: 'README', data: 'Hello world' } },
+        {   
+            dir: { 
+                name: 'images',
+                entries: [
+                    { file: { name: 'cat.jpg', data: new ArrayBuffer(8000) } },
+                    { file: { name: 'lobster.jpg', data: new ArrayBuffer(16000) } },
+                ]
+            }
+        },
+        { 
+            dir: {
+                name: 'src',
+                entries: [
+                    { file: { name: 'index.js', data: 'while (true) alert("You suck!")' } },
+                    { dir: { name: 'empty', entries: [] } },
+                ]
+            }
+        }
+    ]
+});

docs/examples/pointer-example-3.txt

@@ -0,0 +1,8 @@
+root/
+  README (11)
+  images/
+    cat.jpg (8000)
+    lobster.jpg (16000)
+  src/
+    index.js (31)
+    empty/

docs/examples/pointer-example-3.zig

@@ -0,0 +1,40 @@
+const std = @import("std");
+
+pub const File = struct {
+    name: []const u8,
+    data: []const u8,
+};
+pub const Directory = struct {
+    name: []const u8,
+    entries: []const DirectoryEntry,
+};
+pub const DirectoryEntry = union(enum) {
+    file: File,
+    dir: Directory,
+};
+
+fn indent(depth: u32) void {
+    for (0..depth) |_| {
+        std.debug.print("  ", .{});
+    }
+}
+
+fn printFile(file: File, depth: u32) void {
+    indent(depth);
+    std.debug.print("{s} ({d})\n", .{ file.name, file.data.len });
+}
+
+fn printDirectory(dir: Directory, depth: u32) void {
+    indent(depth);
+    std.debug.print("{s}/\n", .{dir.name});
+    for (dir.entries) |entry| {
+        switch (entry) {
+            .file => |f| printFile(f, depth + 1),
+            .dir => |d| printDirectory(d, depth + 1),
+        }
+    }
+}
+
+pub fn printDirectoryTree(dir: Directory) void {
+    printDirectory(dir, 0);
+}