suzanne.soy/typed-racket
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Allow an implicit paren for (: <id> : T ... -> T)

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svn: r12038

original commit: 9cc7f90a0aa877aab3310a83b1f3133105d2aefa
This commit is contained in:
Eli Barzilay 2008-10-14 18:44:05 +00:00
parent 557bd01043
commit cec84d33dd
1 changed files with 22 additions and 18 deletions
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40
collects/typed-scheme/private/prims.ss
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@ -160,24 +160,28 @@ This file defines two sorts of primitives. All of them are provided into any mod
(syntax-property #'arg 'type-ascription #'ty)]))
(define-syntax (: stx)
(let ([stx*
;; make it possible to add another colon after the id for clarity
(syntax-case stx (:)
[(: id : . more) (syntax/loc stx (: id . more))]
[_ stx])])
(syntax-case stx* ()
[(_ id ty)
(identifier? #'id)
(syntax-property
(internal (syntax/loc stx (:-internal id ty)))
'disappeared-use #'id)]
[(_ id ty)
(raise-syntax-error '|type declaration| "can only annotate identifiers with types"
stx #'id)]
[(_ _ _ _ . _)
(raise-syntax-error '|type declaration| "too many arguments" stx)]
[(_ _)
(raise-syntax-error '|type declaration| "too few arguments" stx)])))
(define stx*
;; make it possible to add another colon after the id for clarity
;; and in that case, a `->' on the RHS does not need to be
;; explicitly parenthesized
(syntax-case stx (:)
[(: id : first x ... last)
(ormap (lambda (x) (eq? '-> (syntax-e x))) (syntax->list #'(x ...)))
(syntax/loc stx (: id (first x ... last)))]
[(: id : . more) (syntax/loc stx (: id . more))]
[_ stx]))
(define (err str . sub)
(apply raise-syntax-error '|type declaration| str stx sub))
(syntax-case stx* ()
[(_ id ty)
(identifier? #'id)
(syntax-property (internal (syntax/loc stx (:-internal id ty)))
'disappeared-use #'id)]
[(_ id x ...)
(case (length (syntax->list #'(x ...)))
[(1) (err "can only annotate identifiers with types" #'id)]
[(0) (err "missing type")]
[else (err "bad syntax (multiple types after identifier)")])]))
(define-syntax (inst stx)
(syntax-case stx (:)