Differences from The Reasoned Schemer

The following are the most important differences from version of miniKanren described in The Reasoned Schemer (TRS).

• #s is s#
• #u is u#
• fresh is exist
• conde is actually condi. There is no conde as is presented in the book. This means the order of results may not match what is shown in the book.
• conde does not support defining an else clause.
• the run interface returns a lazy-sequence not a list
• Clojure has no way to create pairs (sequences with improper tails). The core.logic lcons constructor fn provides this behavior. llist is a convenience macro that expands out into nested lcons expressions.
• nullo is emptyo
• nilo unifies with nil
• caro is firsto
• cdro is resto

For example TRS 2-52 (Chapter 2, #52) is written like so in Scheme:

(run #f (r)
  (fresh (x y)
    (== (cons x (cons y 'salad)) r)))

It can be written like this in core.logic:

(run* [r]
  (exist [x y]
    (== (lcons x (lcons y 'salad)) r)))

TRS 3-10 is written like so in Scheme:

(run 1 (x)
  (listo '(a b c . x)))

Can be written like this in core.logic:

(run 1 [x]
  (listo (llist a b c x)))

There is no predicate pair?, however you can provide one yourself with the following:

(defn pair? [x]
   (or (lcons? x) (and (coll? x) (seq x))))

Related, implementing list? as shown in TRS 3-1 is unnecessary. seq? is more appropiate in Clojure. This is because proper list-like things and pairs are not conflated in Clojure as they are in Scheme. In general you should not use vectors when working through TRS. Use list or a quoted list. TRS examples that use Scheme quasiquote will need to written like so (TRS 3-7):

(run* [x]
   (listo (list 'a 'b x 'd)))