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Fixed define-pvars (was not defining the unique-at-runtime variables)

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This commit is contained in:
Georges Dupéron 2017-01-27 22:04:37 +01:00
parent 81a05e6ff3
commit 0029c1acbf
2 changed files with 10 additions and 7 deletions
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11
current-pvars.rkt
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@ -88,7 +88,7 @@
(λ (lower upper)
(if (= (- upper lower) 1)
(if (try-nth-current-pvars upper)
upper
upper ;; Technically not possible, still included for safety.
lower)
(let ([mid (/ (+ upper lower) 2)])
(if (try-nth-current-pvars mid)
@ -186,6 +186,9 @@
(nth-current-pvars-id (+ old-pvars-index 1)))])
(datum->syntax
(quote-syntax here)
`(define-syntaxes (,binding)
(list* ,@stxquoted-pvars+unique
(try-nth-current-pvars ,old-pvars-index))))))))
`(begin
(define-values (,@unique-at-runtime)
(values ,@(map (λ (pvar) `(gensym (quote ,pvar))) pvars)))
(define-syntaxes (,binding)
(list* ,@stxquoted-pvars+unique
(try-nth-current-pvars ,old-pvars-index)))))))))

6
scribblings/stxparse-info.scrbl
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@ -26,10 +26,10 @@ and the @racket[syntax-case] family. These patched versions track which syntax
pattern variables are bound. This allows some libraries to change the way
syntax pattern variables work.
For example, @racketmodname[subtemplate] automatically derives temporary
For example, @tt{subtemplate} automatically derives temporary
identifiers when a template contains @racket[yᵢ …], and @racket[xᵢ] is a
pattern variable. To know from which @racket[varᵢ] the @racket[yᵢ …]
identifiers must be derived, @racketmodname[subtemplate] needs to know which
identifiers must be derived, @tt{subtemplate} needs to know which
syntax pattern variables are within scope.
@section{Tracking currently-bound pattern variables with @racket[syntax-parse]}
@ -86,7 +86,7 @@ track which syntax or datum pattern variables are bound.
This can be used to associate run-time data with each syntax pattern
variable, via a weak hash table created with @racket[make-weak-hasheq]. For
example, the @racketmodname[subtemplate] library implicitly derives
example, the @tt{subtemplate} library implicitly derives
identifiers (similarly to @racket[generate-temporaries]) for uses of
@racket[yᵢ ...] from a @racket[xᵢ] pattern variable bearing the same
subscript. The generated identifiers are associated with @racket[xᵢ] via this