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allow empty splicing-syntax-parameterize body in a defn context (PR 10311)

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svn: r15251
This commit is contained in:
Matthew Flatt 2009-06-24 13:17:17 +00:00
parent be229c2f5e
commit 7f019819e0
4 changed files with 14 additions and 7 deletions
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12
collects/scheme/private/stxparam.ss
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@ -11,9 +11,9 @@
(#%provide (for-syntax do-syntax-parameterize)) (#%provide (for-syntax do-syntax-parameterize))
(define-for-syntax (do-syntax-parameterize stx let-syntaxes-id) (define-for-syntax (do-syntax-parameterize stx let-syntaxes-id empty-body-ok?)
(syntax-case stx () (syntax-case stx ()
[(_ ([id val] ...) body0 body ...) [(_ ([id val] ...) body ...)
(let ([ids (syntax->list #'(id ...))]) (let ([ids (syntax->list #'(id ...))])
(with-syntax ([(gen-id ...) (with-syntax ([(gen-id ...)
(map (lambda (id) (map (lambda (id)
@ -43,7 +43,13 @@
"duplicate binding" "duplicate binding"
stx stx
dup))) dup)))
(unless empty-body-ok?
(when (null? (syntax-e #'(body ...)))
(raise-syntax-error
#f
"missing body expression(s)"
stx)))
(with-syntax ([let-syntaxes let-syntaxes-id]) (with-syntax ([let-syntaxes let-syntaxes-id])
(syntax/loc stx (syntax/loc stx
(let-syntaxes ([(gen-id) (convert-renamer val)] ...) (let-syntaxes ([(gen-id) (convert-renamer val)] ...)
body0 body ...)))))]))) body ...)))))])))

4
collects/scheme/splicing.ss
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@ -169,9 +169,9 @@
(define-syntax (splicing-syntax-parameterize stx) (define-syntax (splicing-syntax-parameterize stx)
(if (eq? 'expression (syntax-local-context)) (if (eq? 'expression (syntax-local-context))
;; Splicing is no help in an expression context: ;; Splicing is no help in an expression context:
(do-syntax-parameterize stx #'let-syntaxes) (do-syntax-parameterize stx #'let-syntaxes #f)
;; Let `syntax-parameterize' check syntax, then continue ;; Let `syntax-parameterize' check syntax, then continue
(do-syntax-parameterize stx #'ssp-let-syntaxes))) (do-syntax-parameterize stx #'ssp-let-syntaxes #t)))
(define-syntax (ssp-let-syntaxes stx) (define-syntax (ssp-let-syntaxes stx)
(syntax-case stx () (syntax-case stx ()

2
collects/scheme/stxparam.ss
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@ -31,4 +31,4 @@
gen-id))))))])) gen-id))))))]))
(define-syntax (syntax-parameterize stx) (define-syntax (syntax-parameterize stx)
(do-syntax-parameterize stx #'let-syntaxes))) (do-syntax-parameterize stx #'let-syntaxes #f)))

3
collects/scribblings/reference/splicing.scrbl
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@ -66,7 +66,8 @@ forms are valid in an internal-definition context. In particular,
@scheme[require] and @scheme[provide] forms cannot appear in the body @scheme[require] and @scheme[provide] forms cannot appear in the body
of @scheme[splicing-syntax-parameterize], even if of @scheme[splicing-syntax-parameterize], even if
@scheme[splicing-syntax-parameterize] is used in a @scheme[module] @scheme[splicing-syntax-parameterize] is used in a @scheme[module]
body. body. In a definition context, the body of
@scheme[splicing-syntax-parameterize] can be empty.
@examples[ @examples[
#:eval splice-eval #:eval splice-eval