Add minimal examples

examples/004_functions.wl

@@ -0,0 +1,26 @@
+
+<!--
+    You can declare functions too.
+
+    Unlike the global scope, expressions
+    are not printed by default, so you need
+    to use the print statement to do so.
+-->
+
+fun say_hello(name) {
+    print "Hello to "
+    print name
+}
+
+say_hello("cozis")
+
+<!--
+    If a function is implemented with a single
+    expression, you can omit the curly braces
+    to return it
+-->
+
+fun say_hello_2(name)
+    <a>Hello, \name!</a>
+
+say_hello_2("cozis")