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Avoid accidental shadowing of field-names in query-value* and friends

This commit is contained in:
Tony Garnock-Jones 2016-12-12 10:26:50 +13:00
parent 75bc4a8ca5
commit 6a2163bce9
2 changed files with 47 additions and 17 deletions
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34
racket/syndicate/actor.rkt
View File

@ -565,14 +565,14 @@
(syntax-parse stx
[(_ field-name absent-expr P expr on-add:on-add on-remove:on-remove)
(quasisyntax/loc stx
(let ()
(let ((F field-name))
(on (asserted P) #:priority *query-priority*
#,@(schedule-query-handler-stxs (attribute on-add.expr))
(field-name expr))
(F expr))
(on (retracted P) #:priority *query-priority-high*
#,@(schedule-query-handler-stxs (attribute on-remove.expr))
(field-name absent-expr))
field-name))]))
(F absent-expr))
F))]))
(define-syntax (query-set stx)
(syntax-parse stx
@ -586,14 +586,14 @@
(syntax-parse stx
[(_ field-name P expr on-add:on-add on-remove:on-remove)
(quasisyntax/loc stx
(let ()
(let ((F field-name))
(on (asserted P) #:priority *query-priority*
#,@(schedule-query-handler-stxs (attribute on-add.expr))
(field-name (set-add (field-name) expr)))
(F (set-add (F) expr)))
(on (retracted P) #:priority *query-priority-high*
#,@(schedule-query-handler-stxs (attribute on-remove.expr))
(field-name (set-remove (field-name) expr)))
field-name))]))
(F (set-remove (F) expr)))
F))]))
(define-syntax (query-hash stx)
(syntax-parse stx
@ -607,20 +607,20 @@
(syntax-parse stx
[(_ field-name P key-expr value-expr on-add:on-add on-remove:on-remove)
(quasisyntax/loc stx
(let ()
(let ((F field-name))
(on (asserted P) #:priority *query-priority*
(let ((key key-expr))
(when (hash-has-key? (field-name) key)
(when (hash-has-key? (F) key)
(log-warning "query-hash: field ~v with pattern ~v: overwriting existing entry ~v"
'field-name
'P
key))
#,@(schedule-query-handler-stxs (attribute on-add.expr))
(field-name (hash-set (field-name) key value-expr))))
(F (hash-set (F) key value-expr))))
(on (retracted P) #:priority *query-priority-high*
#,@(schedule-query-handler-stxs (attribute on-remove.expr))
(field-name (hash-remove (field-name) key-expr)))
field-name))]))
(F (hash-remove (F) key-expr)))
F))]))
(define-syntax (query-hash-set stx)
(syntax-parse stx
@ -634,14 +634,14 @@
(syntax-parse stx
[(_ field-name P key-expr value-expr on-add:on-add on-remove:on-remove)
(quasisyntax/loc stx
(let ()
(let ((F field-name))
(on (asserted P) #:priority *query-priority*
#,@(schedule-query-handler-stxs (attribute on-add.expr))
(field-name (hashset-add (field-name) key-expr value-expr)))
(F (hashset-add (F) key-expr value-expr)))
(on (retracted P) #:priority *query-priority-high*
#,@(schedule-query-handler-stxs (attribute on-remove.expr))
(field-name (hashset-remove (field-name) key-expr value-expr)))
field-name))]))
(F (hashset-remove (F) key-expr value-expr)))
F))]))
(define-syntax-rule (define/query-value id ae P x ...) (define id (query-value id ae P x ...)))
(define-syntax-rule (define/query-set id P x ...) (define id (query-set id P x ...)))

30
racket/syndicate/examples/actor/example-bug-query-scope.rkt Normal file
View File

@ -0,0 +1,30 @@
#lang syndicate/actor
;; Demonstrates a (fixed) bug in define/query-value scoping.
;;
;; Buggy output:
;;
;; w is #f
;; Process #f (0) died with exception:
;; application: not a procedure;
;; expected a procedure that can be applied to arguments
;; given: '(val 123)
;; arguments...:
;; '(val 123)
;; context...:
;;
;; Expected output:
;;
;; w is #f
;; w is '(val 123)
;;
;; Diagnosis:
;;
;; The field being defined, w, was being shadowed by the w binding in
;; the query pattern. Adding `(let ((F field-name)) ...)` in the
;; query-value* macro (and friends) avoids the issue.
(actor (define/query-value w #f ($ w (list 'val _)) w)
(begin/dataflow
(log-info "w is ~v" (w))))
(actor (assert (list 'val 123)))