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make datum variable in syntax template an error

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Previously, a datum variable was treated as a constant.
This commit is contained in:
Ryan Culpepper 2020-03-02 14:27:14 +01:00
parent 25142daea5
commit 45fb9b4d63
1 changed files with 10 additions and 4 deletions
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14
racket/collects/racket/private/template.rkt
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@ -387,6 +387,7 @@
iter))]))))
(let ([v (syntax-local-value id (lambda () #f))])
(cond [(syntax-pattern-variable? v)
;; syntax variables allowed in both syntax and datum templates
(define pvar-depth (syntax-mapping-depth v))
(define attr
(let ([attr (syntax-local-value (syntax-mapping-valvar v) (lambda () #f))])
@ -394,10 +395,15 @@
(define var (if attr (attribute-mapping-var attr) (syntax-mapping-valvar v)))
(define check (and attr (attribute-mapping-check attr)))
(make-pvar var check pvar-depth)]
[(and (not stx?) (s-exp-pattern-variable? v))
(define pvar-depth (s-exp-mapping-depth v))
(define var (s-exp-mapping-valvar v))
(make-pvar var #f pvar-depth)]
[(s-exp-pattern-variable? v)
(cond [stx?
;; datum variable in syntax template is error
(wrong-syntax id "datum variable not allowed in syntax template")]
[else
;; datum variable in datum template
(define pvar-depth (s-exp-mapping-depth v))
(define var (s-exp-mapping-valvar v))
(make-pvar var #f pvar-depth)])]
[else
;; id is a constant; check that for all x s.t. id = x.y, x is not an attribute
(for-each