run.sx: reify-name builds canonical "_.N" symbols; reify-s walks a term
left-to-right and assigns each unbound var its index in the discovery
order; reify combines the two with two walk* passes. run-n is the
runtime defmacro: binds the query var, takes ≤ n stream answers, reifies
each. run* and run are sugar around it.
First classic miniKanren tests green:
(run* q (== q 1)) → (1)
(run* q (conde ((== q 1)) ((== q 2)))) → (1 2)
(run* q (fresh (x y) (== q (list x y)))) → ((_.0 _.1))
128/128 cumulative.
giles
52070e07fc