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Macro stepper: fail gracefully on frontier-computation errors

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svn: r7231
This commit is contained in:
Ryan Culpepper 2007-08-30 21:44:10 +00:00
parent 9b8abc0275
commit da4c99f231
1 changed files with 20 additions and 15 deletions
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31
collects/macro-debugger/model/reductions-engine.ss
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@ -66,16 +66,18 @@
(define (learn-definites ids)
(current-definites (append ids (current-definites))))
(define (get-frontier) (or (current-frontier) null))
(define (add-frontier stxs)
(current-frontier (append stxs (current-frontier)))
#;(printf "new frontier: ~s~n" (current-frontier)))
(current-frontier
(let ([frontier0 (current-frontier)])
(and frontier0 (append stxs frontier0)))))
(define (blaze-frontier stx)
#;(unless (memq stx (current-frontier))
(fprintf (current-error-port) "frontier does not contain term: ~s~n" stx)
(error 'blaze-frontier))
(current-frontier (remq stx (current-frontier)))
#;(printf "new frontier (blazed): ~s~n" (current-frontier)))
(current-frontier
(let ([frontier0 (current-frontier)])
(and frontier0
(remq stx frontier0)))))
;; -----------------------------------
@ -212,7 +214,10 @@
(define (rename-frontier from to)
(current-frontier
(apply append (map (make-rename-mapping from to) (current-frontier)))))
(with-handlers ([exn:fail? (lambda _ #f)])
(apply append
(map (make-rename-mapping from to)
(current-frontier))))))
(define (make-rename-mapping from0 to0)
(define table (make-hash-table))
@ -262,31 +267,31 @@
;; Lifts a local step into a term step.
(define (walk e1 e2 type)
(make-step (current-derivation) (big-context) type (context)
(current-definites) (current-frontier)
(current-definites) (get-frontier)
(foci e1) (foci e2) e1 e2))
;; walk/foci : syntaxes syntaxes syntax syntax StepType -> Reduction
(define (walk/foci foci1 foci2 Ee1 Ee2 type)
(make-step (current-derivation) (big-context) type (context)
(current-definites) (current-frontier)
(current-definites) (get-frontier)
(foci foci1) (foci foci2) Ee1 Ee2))
;; walk/mono : syntax StepType -> Reduction
(define (walk/mono e1 type)
(make-mono (current-derivation) (big-context) type (context)
(current-definites) (current-frontier)
(current-definites) (get-frontier)
(foci e1) e1))
;; stumble : syntax exception -> Reduction
(define (stumble stx exn)
(make-misstep (current-derivation) (big-context) 'error (context)
(current-definites) (current-frontier)
(current-definites) (get-frontier)
(foci stx) stx exn))
;; stumble/E : syntax(s) syntax exn -> Reduction
(define (stumble/E focus Ee1 exn)
(make-misstep (current-derivation) (big-context) 'error (context)
(current-definites) (current-frontier)
(current-definites) (get-frontier)
(foci focus) Ee1 exn))
;; ------------------------------------