Some tweeks, examples, and sweet ASCII tree because ASCII trees make everything better.

How-to-read-the-standard-library-source-code.md

@@ -4,11 +4,30 @@
 You can find it under [`/lib/std/`](https://github.com/ziglang/zig/tree/master/lib/std).
 
 ## How is the stdlib structured?
-When you import "std" in a Zig source file, you are importing `/lib/std/std.zig`.
-In that file you can see where each exposed symbol comes from.
- 
-Some parts of the stdlib are simple and are implemented in a single file, like `std.ascii`, which is entirely implemented in `/lib/std/ascii.zig`. Some other parts of the standard library are beefier and so have their own dedicated subdirectory, like `std.math`.
-Those beefier "submodules" always have a regular structure: 
+When you import "std" in a Zig source file, you are importing [`/lib/std/std.zig`](https://github.com/ziglang/zig/tree/master/lib/std/std.zig).
+
+```zig
+const std = @import("std");
+```
+
+In that file you can see where each exposed symbol comes from:
+
+```zig
+// Excerpt from std.zig
+...
+pub const ArrayHashMap = array_hash_map.ArrayHashMap;
+pub const ArrayHashMapUnmanaged = array_hash_map.ArrayHashMapUnmanaged;
+pub const ArrayList = @import("array_list.zig").ArrayList;
+pub const ArrayListAligned = @import("array_list.zig").ArrayListAligned;
+pub const ArrayListAlignedUnmanaged = @import("array_list.zig").ArrayListAlignedUnmanaged;
+pub const ArrayListUnmanaged = @import("array_list.zig").ArrayListUnmanaged;
+...
+```
+
+
+Some parts of the stdlib are simple and are implemented in a single file, like `std.ascii`, which is entirely implemented in `/lib/std/ascii.zig`.
+
+Other parts of the standard library are beefier and have their own dedicated subdirectory, like `std.math`. These "submodules" always have a regular structure: 
 - A subdirectory that contains most of the implementation
 - A file inside `/lib/std/` that exposes the public parts implemented in the relative subdirectory
 
@@ -18,6 +37,18 @@ In the case of `std.math`, for example, `/lib/std/math/ceil.zig` contains the im
 pub const ceil = @import("math/ceil.zig").ceil; 
 ```
 
+The directory tree of the `std.ascii` and `std.math` files described above are arranged like so:
+
+```
+.
+`-- lib/
+    `-- std/
+        |-- ascii.zig
+        |-- math/
+        |   `-- ceil.zig
+        `-- math.zig
+```
+
 With this knowledge it should be easy for you to track down the implementation code of every symbol defined in the standard library.
 
 One final trick: search for `pub fn` and `pub const` to quickly skim over the public API of an implementation.