;; lib/maude/tests/searchpath.sx — search returning the witness path.

(define msp-pass 0)
(define msp-fail 0)
(define msp-failures (list))

(define
  msp-check!
  (fn
    (name got expected)
    (if
      (= got expected)
      (set! msp-pass (+ msp-pass 1))
      (do
        (set! msp-fail (+ msp-fail 1))
        (append!
          msp-failures
          (str name "  expected: " expected "  got: " got))))))

(define
  msp-ndet
  (mau/parse-module
    "mod NDET is\n  sort S .\n  ops a b c d goal : -> S .\n  rl [r1] : a => b .\n  rl [r2] : a => c .\n  rl [r3] : b => d .\n  rl [r4] : c => goal .\nendm"))

;; shortest path a -> c -> goal
(msp-check!
  "path-to-goal"
  (mau/search-path msp-ndet "a" "goal" 5)
  (list "a" "c" "goal"))
(msp-check!
  "path-length"
  (mau/search-length msp-ndet "a" "goal" 5)
  2)
(msp-check!
  "path-self"
  (mau/search-path msp-ndet "a" "a" 3)
  (list "a"))
(msp-check!
  "path-one-step"
  (mau/search-path msp-ndet "a" "b" 3)
  (list "a" "b"))
(msp-check!
  "path-unreachable"
  (mau/search-path msp-ndet "d" "goal" 5)
  nil)
(msp-check!
  "path-depth-limited"
  (mau/search-path msp-ndet "a" "goal" 1)
  nil)

;; a counter that ticks up: path shows each state
(define
  msp-walk
  (mau/parse-module
    "mod WALK is\n  sort Pos .\n  op z : -> Pos .\n  op s : Pos -> Pos .\n  op p : Pos -> Pos .\n  var X : Pos .\n  rl [step] : p(X) => p(s(X)) .\nendm"))

(msp-check!
  "walk-path"
  (mau/search-path msp-walk "p(z)" "p(s(s(z)))" 5)
  (list "p(z)" "p(s(z))" "p(s(s(z)))"))
(msp-check!
  "walk-length"
  (mau/search-length msp-walk "p(z)" "p(s(s(s(z))))" 6)
  3)

(define mau-searchpath-tests-run! (fn () {:failures msp-failures :total (+ msp-pass msp-fail) :passed msp-pass :failed msp-fail}))