From d0516947bf783e28697be1b0fc3df3b4e6d1a73c Mon Sep 17 00:00:00 2001 From: Matthew Butterick Date: Sun, 5 Oct 2014 08:54:56 -0700 Subject: [PATCH] blits --- csp/solver.rkt | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) diff --git a/csp/solver.rkt b/csp/solver.rkt index 75dddd16..6173d4fd 100644 --- a/csp/solver.rkt +++ b/csp/solver.rkt @@ -1,5 +1,5 @@ #lang racket/base -(require racket/class sugar/container racket/list racket/generator racket/match "helper.rkt") +(require racket/class sugar/container sugar/debug racket/list racket/generator racket/match "helper.rkt") (provide (all-defined-out)) (define solver% @@ -46,11 +46,10 @@ (list (* -1 (length (hash-ref vconstraints variable))) (length ((hash-ref domains variable))) variable)) list-comparator)) - ;(report lst) - (let/ec break-for-loop - (for ([last-item (in-list (map last work-list))] - #:when (not (hash-has-key? assignments last-item))) - ; Found unassigned variable + + (define found-unassigned-variable? + (for/first ([last-item (in-list (map last work-list))] + #:when (not (hash-has-key? assignments last-item))) (set! variable last-item) (set! values ((hash-ref domains variable))) (set! pushdomains @@ -60,14 +59,13 @@ (not (equal? variable x)))) (hash-ref domains x)) null)) - (break-for-loop)) - - ;; if it makes it through the loop without breaking, then there are - ;; no unassigned variables. We've got a solution. + variable)) + + ;; if there are no unassigned variables, we've got a solution. + (when (not found-unassigned-variable?) (yield (hash-copy assignments)) - - ;; Return to previous variable in queue if possible, otherwise all done (cond + ;; Return to previous variable in queue if possible, otherwise all done [(not (null? queue)) (set!-values (variable values pushdomains) (pop-vvp-values! queue)) (for-each-send pop-state pushdomains)]