Hi Jon, Thanks, that works perfectly!
Did I miss that somewhere in the documentation? I don't recall seeing an example of it. Best, Nick On Thu, Aug 2, 2012 at 11:55 PM, Jon Rafkind <rafk...@cs.utah.edu> wrote: > To match a literal ellipses in syntax-parse use #:literal [(ellipses ...)] > and match on the term `ellipses', then to use a literal ellipses in the > template use (... ...) instead of just ... > > It looks like you only want the latter, so > > (define-syntax (example stx) > (syntax-parse stx > [(_ name:id) #'(define-syntax (name stx) > (syntax-parse stx > [(_ args (... ...)) #'(args (... ...)))])])) > > On 08/02/2012 11:30 PM, Nick Sivo wrote: >> Hi, >> >> I'm trying to use ... in the inner macro of a macro defining macro, >> but can't figure out the right way to escape it. >> >> Here's a minimal (pointless) example: >> >> (require (for-syntax syntax/parse)) >> >> (define-syntax (example stx) >> (syntax-parse >> stx >> ;#:literals (...) ; Doesn't help :( >> [(_ name:id) >> #'(define-syntax (name stx) >> (syntax-parse >> stx >> [(_ args ...) #'(args ...)]))])) >> >> The goal is to have (example invisible) define a macro called >> invisible that erases itself. >> >> Any ideas? The full code I'm trying to enable follows below if you'd >> like more context. >> >> Thanks, >> Nick >> >> #lang racket >> >> (require (for-syntax syntax/parse) >> racket/splicing) >> >> ;;; >> ;;; Procedure Application >> ;;; >> >> (define arc-nil #f) >> >> (define-syntax (arc-#%app stx) >> (syntax-parse >> stx >> [(_ fn:expr arg:expr) >> #'(let ([efn fn]) >> (cond [(procedure? efn) (#%app efn arg)] >> [(pair? efn) (#%app list-ref efn arg)] >> [(string? efn) (#%app string-ref efn arg)] >> [(hash? efn) (#%app hash-ref efn arg arc-nil)] >> [else (#%app efn arg)]))] >> [(_ fn:expr arg1:expr arg2:expr) >> #'(let ([efn fn]) >> (if (hash? efn) >> ; Have to use the lamda in case arg2 is a function >> ; See hash-ref docs for more info >> (#%app hash-ref fn arg1 (lambda () arg2)) >> (#%app fn arg1 arg2)))] >> [(_ args ...) >> #'(#%app args ...)])) >> >> ; This allows cross module mutation of globals >> (define-syntax (declare-with-set-transformer stx) >> (syntax-parse >> stx >> ;#:literals (...) ; Doesn't help :( >> [(_ var:id) >> #'(declare-with-set-transformer var (gensym 'unintialized))] >> [(_ var:id init-val:expr) >> (let ([store-name (gensym (syntax->datum #'var))]) >> #`(begin >> (define #,store-name init-val) >> (splicing-let ([set (lambda (val) >> (set! #,store-name val))]) >> (define-syntax var >> (make-set!-transformer >> (lambda (stx) >> (syntax-case stx (set!) >> [(set! id val) #'(set val)] >> ; Uses Racket's #%app, which doesn't work for arc >> [(id . args) #'(#,store-name . args)] ; function >> application >> ; Obviously invalid syntax >> ;[(id . args) #'(arc-#%app #,store-name . args)] >> ; Errors because ... isn't recognized as a literal >> ;[(id args ...) #'(arc-#%app #,store-name args ...)] >> [id (identifier? #'id) #'#,store-name])))))))])) >> >> ; Demo of what I'm looking for >> (define test (make-hash)) >> (hash-set! test 'key 'value) >> (displayln (arc-#%app test 'key)) >> >> ; Example of what doesn't work right now >> (declare-with-set-transformer test2 (make-hash)) >> (hash-set! test2 'key 'value) >> (displayln (test2 'key)) >> ____________________ >> Racket Users list: >> http://lists.racket-lang.org/users > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
