Implemented an abstract syntax tree

src/build/keyword/Keyword.go

@@ -0,0 +1,12 @@
+package keyword
+
+const (
+	Loop   = "loop"
+	Return = "return"
+)
+
+// Map is a map of all keywords used in the language.
+var Map = map[string][]byte{
+	Loop:   []byte(Loop),
+	Return: []byte(Return),
+}