sample-code: Add match_test.cl

Demonstrates pattern matching

sample-code/match_test.cl

@@ -0,0 +1,18 @@
+//! This is a Conlang library demonstrating `match`
+
+struct Student {
+    name: str,
+    age: i32,
+}
+
+fn Student (name: str, age: i32) -> Student {
+    Student: { name, age }
+}
+
+fn match_test(student: Student) {
+    match student {
+        Student: { name: "shark", age } => println("Found a shark of ", age, " year(s)"),
+        Student: { name, age: 22 } => println("Found a 22-year-old named ", name),
+        Student: { name, age } => println("Found someone named ", name, " of ", age, " year(s)"),
+    }
+}