Interpreter - call internal procedures

code/demo.odin

@@ -1,6 +1,11 @@
 #import "fmt.odin"
 
 main :: proc() {
+	foo :: proc(x: i64) -> i64 {
+		return -x + 1
+	}
+
 	x, y: i64 = 123, 321
 	y = x + 2 - y
+	x = foo(y)
 }