Implemented switch statements

src/build/ast/Switch.go

@@ -0,0 +1,16 @@
+package ast
+
+import (
+	"git.akyoto.dev/cli/q/src/build/expression"
+)
+
+// Switch represents a switch statement.
+type Switch struct {
+	Cases []Case
+}
+
+// Case represents a case inside a switch.
+type Case struct {
+	Condition *expression.Expression
+	Body      AST
+}