On Aug 7, 2014, at 9:39 AM, Alexander D. Knauth <[email protected]> wrote:
> > On Aug 7, 2014, at 1:41 AM, Kevin Forchione <[email protected]> wrote: > >> >> On Aug 6, 2014, at 11:02 AM, Alexander D. Knauth <[email protected]> >> wrote: >> >>> >>> On Aug 6, 2014, at 1:47 PM, Alexander D. Knauth <[email protected]> >>> wrote: >>> >>>> >>>> >>>> On Aug 6, 2014, at 1:10 PM, Kevin Forchione <[email protected]> wrote: >>>> >>>>> >>>>> On Aug 5, 2014, at 2:21 PM, Jens Axel Søgaard <[email protected]> >>>>> wrote: >>>>> >>>>>> Is this a step in the right direction? >>>>>> >>>>>> (define-syntax (x stx) >>>>>> (syntax-parse stx >>>>>> [(_ (y ... (z ...) w ...)) >>>>>> #'(xf (yf y ... (zf z ...) w ...))])) >>>>>> >>>>>> The pattern (z ...) ... will match a sequence of lists such as (4 5 6) >>>>>> (7 8) >>>>>> but it won't match (4 5 6) 7 8 from your example. >>>>>> >>>>>> /Jens Axel >>>>> >>>>> Closer. It doesn’t match something like ‘( 1 2 3 (4 5 6) 7 (8 9) 10), for >>>>> instance. >>>> >>>> For that I think you want something like this: >>>> (syntax-parse stx >>>> [(_ (~or (z ...) >>>> y) >>>> ...) >>>> #'(xf (yf y ... (zf z ...)))]) >>> >>> Sorry I forgot an ellipsis. I meant this: >>> (syntax-parse stx >>> [(_ (~or (z ...) >>> y) >>> ...) >>> #'(xf (yf y ... (zf z ...) ...))]) >> >> >> Remarkably difficult just to parse what amounts to nested lists! This >> doesn’t quite do what I want either. For instance: >> >> #lang racket >> >> (require (for-syntax syntax/parse)) >> >> #;(define-syntax (x stx) >> >> (define-syntax-class binding >> #:description "binding list" >> (pattern (z:number ...))) >> >> (syntax-parse stx >> [(_ b:binding ...) >> #'(list (list b.z ...) ...)])) >> >> #;(define-syntax (x stx) >> >> (define-syntax-class lbinding >> #:description "binding list" >> (pattern (z:number ...))) >> >> (define-syntax-class orbinding >> #:description "binding or" >> (pattern (y:number ...) >> #:with (z ...) #'(y ...)) >> (pattern (lb:lbinding) >> #:with (z ...) #'(lb.z ...))) >> >> (syntax-parse stx >> [(_ ob:orbinding ...) >> #'(list (list ob.z ...) ...)])) >> >> #;(define-syntax (x stx) >> >> (define-syntax-class lbinding >> #:description "binding list" >> (pattern (z:number ...))) >> >> (define-syntax-class orbinding >> #:description "binding or" >> (pattern (y:number ...) >> #:with (z ...) #'(y ...)) >> (pattern (lb:lbinding) >> #:with (z ...) #'(lb.z ...))) >> >> (syntax-parse stx >> [(_ ob:orbinding ...) >> #'(list (list ob.z ...) ...)])) >> >> (define-syntax (x stx) >> (syntax-parse stx >> [(_ (~or (z ...) >> y) >> ...) >> #'(list (list y ... (list z ...) ...))])) >> >> (x (1 2 3 4) (5 (6 7) 8)) >> >> expands to: (list (list (list 1 2 3 4) (list 5 (6 7) 8))))) instead of >> (list (list (list 1 2 3 4) (list 5 (list 6 7) 8))))). >> >> -Kevin >> > > Do you want something like this then: > (syntax-parse stx > [(_ (~or ((((e ...) ...) ...) ...) > (((d ...) ...) ...) > ((c ...) ...) > (b ...) > a) > . . .) > #’(list (list a ... (list b ... (list c ... (list d ... (list e ...) ...) > ...) ...) ...) ...)]) Sorry I meant this: (syntax-parse #'(x (1 2 3 4) (5 (6 7) 8)) [(_ (~or ((~or ((~or ((~or (e ...) d) ...) c) ...) b) ...) a) ...) #'(list (list a ... (list b ... (list c ... (list d ... (list e ...) ...) ...) ...) ...))]) > Except going infinitely? For that I think you would need a recursive helper > function. > > Or do you want to just replace all instances of (a ...) with (list a ...) ?: > (define-syntax-class thing > #:attributes (norm) > [pattern (a:thing ...) > #:with norm (list a.norm ...)] > [pattern a > #:with norm a]) > > Or what? > >
____________________ Racket Users list: http://lists.racket-lang.org/users
