(Details of my miniKanren in Racket setup appear at the bottom[1].)
The way quotes and unquotes work in The Reasoned Schemer appears not to match the way they work in Racket. For instance, verse 2 of chapter 2 suggests[2] the following function definition:
(run #f
(r )
(fresh (y x )
(== '(,x ,y) r )))
If I evaluate that, I get '((,x ,y)). If instead I rewrite it as this:
(run #f
(r )
(fresh (y x )
(== (list x y) r)))
I get the expected result, '((_.0 _.1)).
This might seem like a minor problem, but in many cases the required translation is extremely verbose. For instance, in exercise 45 of chapter 3 (page 34), the book provides, roughly[3] the following definition:
(run 5 (r)
(fresh (w x y z)
(loto (('g 'g) ('e w) (x y) . z))
(== (w (x y) z) r)))
In order to get the results they get, I had to rewrite it like this:
(run 5 (r)
(fresh (w x y z)
(loto (cons '(g g)
(cons (list 'e w)
(cons (list x y)
z))))
(== (list w (list x y) z)
r)))
[1] As described here, I ran raco pkg install minikanren and then defined a few missing pieces.
[2] Actually, they don't write precisely that, but if you heed the advice in the footnotes to that verse and an earlier verse, it's what you get.
[3] Modulo some implicit quoting and unquoting that I cannot deduce.
Use the backquote ` instead of the simple quote ' you have been using.