title: Dr Racket, R5RS and SRFI
body: <p>Whenever I try to use srfi/1 functions like <strong>fold</strong> and <strong>reduce</strong> in drracket r5rs language I get an null-list? error. After some research I found that it is due to the fact that the function requires and immutable list but gets a mutable one. How do I create immutable list in r5rs or is this srfi/1 not designed with r5rs in mind?</p>