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Disunification bug fix.

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After parameter elimination, check the results to
make sure some pre-existing equality hasn't been
reproduced.
This commit is contained in:
Burke Fetscher 2013-11-12 14:55:45 -06:00
parent 1b08b03262
commit 8b17d99d44
1 changed files with 19 additions and 9 deletions
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28
pkgs/redex-pkgs/redex-lib/redex/private/pat-unify.rkt
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@ -38,6 +38,7 @@
make-uid)
;;
;; atom := `any | `number | `string | `integer | `boolean | `real | `variable | `variable-not-otherwise-mentioned
;; var := symbol?
@ -177,7 +178,7 @@
(list->dq-pairs dq-sides/id)))]
[found-dqs
(for/list ([pdq found-pre-dqs])
(disunify* '() (first pdq) (second pdq) (hash-copy static-eqs) L))])
(disunify* '() (first pdq) (second pdq) static-eqs L))])
(and/fail (for/and ([d found-dqs]) d)
(let* ([real-dqs (filter (λ (dq) (not (boolean? dq))) found-dqs)]
[new-dqs (check-and-resimplify static-eqs (append real-dqs (env-dqs e)) L)])
@ -202,19 +203,19 @@
(define eqs (hash-copy (env-eqs e)))
(define t* (bind-names t eqs L))
(define u* (bind-names u eqs L))
(define bn-eqs (hash/mut->imm eqs))
(cond
[(or (unif-fail? t*) (unif-fail? u*))
e]
[else
(define bn-eqs (hash-copy eqs))
(define new-dq (disunify* params t* u* eqs L))
(define new-dq (disunify* params t* u* bn-eqs L))
(match new-dq
[#f #f]
[#t
(env (hash/mut->imm bn-eqs)
(env bn-eqs
(env-dqs e))]
[_
(env (hash/mut->imm bn-eqs)
(env bn-eqs
(cons new-dq
(env-dqs e)))])])))
@ -293,14 +294,15 @@
[else
(match notok
[`(,(dq ps `(,vars-p* ,term-p*)) ,rest ...)
(let ([new-dq (disunify* ps vars-p* term-p* (hash-copy eqs) L)])
(let ([new-dq (disunify* ps vars-p* term-p* eqs L)])
(and new-dq
(match new-dq
[#t (loop ok rest)]
[_ (loop (cons new-dq ok) rest)])))])])))
;; disunfy* pat* pat* eqs lang -> dq or boolean (dq is a pat*)
(define (disunify* params u* t* eqs L)
(define (disunify* params u* t* static-eqs L)
(define eqs (hash-copy static-eqs))
(parameterize ([new-eqs (make-hash)])
(let ([res (unify* u* t* eqs L)])
(cond
@ -312,8 +314,16 @@
(match new-dq
[`((list) (list))
#f]
[_
(dq new-ps new-dq)])]))))
[`((list (name ,var-ids ,(bound)) ...) (list ,pats ...))
;; check to see if parameter elimination exposed some
;; equivalences...
(and
(or (equal? (length params) (length new-ps))
(for/and ([v (in-list var-ids)] [p (in-list pats)])
(or (not (hash-has-key? static-eqs (lvar v)))
(not (equal? (resolve-no-nts/pat `(name ,v ,(bound)) static-eqs)
p)))))
(dq new-ps new-dq))])]))))
(define (param-elim params unquantified-dq)
(let loop ([dq-rest unquantified-dq]