Book Updates

-add chapter 5.3

Author: ktechhydle

book/chapter5.3.md

@@ -0,0 +1,35 @@
+---
+title: "Chapter 5.3"
+---
+
+# Chapter 5.3: Unique Collections
+
+GLang provides a unique collection in its standard library, [`std_hashmap`](/docs/modules/std_hashmap).
+
+The `std_hashmap` module isn’t built in by default, so you’ll need to import it using the `fetch` keyword. We’ll cover `fetch` in more detail later, but for now, just add it to the top of your file.
+
+```
+fetch std_hashmap;
+
+obj my_hashmap = hashmap();
+hashmap_set(my_hashmap, "name", "Bob");
+hashmap_set(my_hashmap, "favorite-color", "Green");
+````
+
+A hashmap is a collection of key–value pairs, think of it like a small, efficient lookup table.
+
+| Key              | Value   |
+| ---------------- | ------- |
+| `name`           | `Bob`   |
+| `favorite-color` | `Green` |
+
+You can **set** new entries by providing a key and value, or **get** existing values by their corresponding keys.
+
+```
+fetch std_hashmap;
+
+obj my_hashmap = hashmap();
+hashmap_set(my_hashmap, "name", "Bob");
+
+obj name = hashmap_get(my_hashmap, "name"); # 'Bob'
+```