suzanne.soy/extensible-parser-specifications
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Put 'none back as a result for ~global-and with no matches.

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This commit is contained in:
Georges Dupéron 2016-09-19 21:00:39 +02:00
parent 8ac38f4a3a
commit 8c1b7dcf13
2 changed files with 14 additions and 7 deletions
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10
private/global.rkt
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@ -44,11 +44,13 @@
(make-~global #'aggregate-global-or #'#t)) (make-~global #'aggregate-global-or #'#t))
(define (aggregate-global-and . bs) (define (aggregate-global-and . bs)
(true? ;; force the result to be a boolean, the order of terms is unimportant (let ([matches (filter identity ;; remove failed bindings
(flatten bs))])
(if (null? matches)
'none ;; no matches occurred
(true? ;; coerce to boolean, so that the order of terms is unimportant
(andmap unbox ;; remove the layer of protection (andmap unbox ;; remove the layer of protection
(cons (box-immutable 'none) ;; default value when no bindings matched matches))))) ;; don't care about ellipsis nesting
(filter identity ;; remove failed bindings
(flatten bs)))))) ;; don't care about ellipsis nesting
(define-eh-mixin-expander ~global-and (define-eh-mixin-expander ~global-and
(make-~global #'aggregate-global-and)) (make-~global #'aggregate-global-and))

9
scribblings/extensible-parser-specifications.scrbl
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@ -262,8 +262,13 @@ the notion of order irrelevant.
matches of a global pattern using the same @racket[#,tribute-name]. See above matches of a global pattern using the same @racket[#,tribute-name]. See above
for a description of how global operations work. for a description of how global operations work.
The result is always transformed into a boolean, so @racket[_attribute-name] is If there is at least one occurrence of @racket[~global-and] for that
always bound to either @racket[#t] or @racket[#f].} @racket[_attribute-name] which successfully matches, the result of the
@racket[(and valueᵢ ...)] is always coerced to a boolean, so
@racket[_attribute-name] is always bound to either @racket[#t] or @racket[#f].
If there are no matches at all, the special value @racket['none] is used
instead of @racket[#t] as would be produced by @racket[(and)].}
@defform[(~global-counter attribute-name+value #,ntax-pattern ...) @defform[(~global-counter attribute-name+value #,ntax-pattern ...)
#:grammar #:grammar