[plt-scheme] Dot-notation for structure field access

Hi Sam,
Thanks for the tip, but it does not help.
Actually I sent an unnecessary complicated version, but as I think the problem is the same one there, I wont cluther up this list with another version.
Jos

(((((lambda(x)((((((((x x)x)x)x)x)x)x)x))
    (lambda(x)(lambda(y)(x(x y)))))
   (lambda(x)(x)x))
  (lambda()(printf "Greetings, Jos~n"))))
  ----- Original Message ----- 
  From: Sam TH 
  To: jos koot 
  Cc: plt-scheme at list.cs.brown.edu ; Jens Axel Søgaard 
  Sent: Sunday, March 11, 2007 2:52 PM
  Subject: Re: [plt-scheme] Dot-notation for structure field access


  I haven't tested this, but you almost certainly need to add

  (require-for-template mzscheme)

  to the `dot' module.

  Hope that helps,

  sam th

  On 3/11/07, jos koot <jos.koot at telefonica.net> wrote:
  >
  >
  > Hi,
  > Inspired by the dot notation of Jens Axel Søgaard I tried to eliminate the
  > need for define-accessor. See enclosure. However, I can't get rid of the
  > error reported at the end of my trial, reading:
  > "compile: bad syntax; reference to top-level identifier is not allowed,
  > because no #%top syntax transformer is bound in: acc85"
  >
  > Can anyone help me, please. Sorry that I don't send a stripped version of
  > the problem. I have tried many stripped versions of my code, but in these
  > the problem does not occur.
  >
  > Greetings, Jos Koot
  >
  > (((((lambda(x)((((((((x x)x)x)x)x)x)x)x))
  >     (lambda(x)(lambda(y)(x(x y)))))
  >    (lambda(x)(x)x))
  >   (lambda()(printf "Greetings, Jos~n"))))
  >
  >
  > ----- Original Message -----
  > From: Jens Axel Søgaard
  > To: George Herson
  > Cc: plt-scheme at list.cs.brown.edu
  > Sent: Thursday, March 08, 2007 11:13 PM
  > Subject: [plt-scheme] Dot-notation for structure field access
  >
  > George Herson skrev:
  >
  > > May not be the best approach but I'm enjoying the
  > > compactness of the resulting code (which allows
  > > conventional table-name.column-name notation in a
  > > sql-like mini-language).
  >
  > That remark sparked inspired me to play a little
  > with #top in order to get the following to work:
  >
  > (require dot)
  > (define-struct color (r g b) (make-inspector))
  >
  > (define-accessor r color-r)
  > (define-accessor g color-g)
  > (define-accessor b color-b)
  >
  > (define a (make-color 1 2 3))
  > a.r  ; evaluates to 1
  > a.g  ; evaluates to 2
  > a.b  ; evaluates to 3
  >
  >
  > The entire program, which by no means is well-tested, is below.
  >
  > /Jens Axel
  >
  > ; Put the entire program in a buffer, choose "Pretty Big"
  > ; and click "Run".
  >
  > (module dot-helper mzscheme
  >    (provide dot define-accessor)
  >
  >    (begin-for-syntax
  >      (define accessors (list)))
  >
  >    (require-for-syntax (prefix srfi: (lib "1.ss" "srfi")))
  >    (define-syntax (dot stx)
  >      (syntax-case stx ()
  >        [(dot expr accessor)
  >         #`(#,(cdr (srfi:assoc #'accessor accessors module-identifier=?))
  >              expr)]))
  >
  >    (define-syntax (define-accessor stx)
  >      (syntax-case stx ()
  >        [(define-accessor name getter)
  >         (begin
  >           (set! accessors (cons (cons #'name #'getter)
  >                                 accessors))
  >           #'(void))])))
  >
  > (module dot mzscheme
  >    (provide (rename my-top #%top)
  >             define-accessor
  >             dot)
  >
  >    (require (lib "pregexp.ss")
  >             dot-helper)
  >
  >    (define-for-syntax (contains-dot? sym)
  >      (member #\. (string->list
  >                   (symbol->string sym))))
  >
  >    (define-for-syntax (split-at-dot sym)
  >      (cond
  >        [(regexp-match #rx"^([^.]*)\\.([^.]*)$" (symbol->string sym))
  >         =>(lambda (result)
  >             (values (string->symbol (list-ref result 1))
  >                     (string->symbol (list-ref result 2))))]
  >        [else #f]))
  >
  >    (define-syntax (my-top stx)
  >      (syntax-case stx ()
  >        [(_ . name)
  >         (and (identifier? #'name)
  >              (contains-dot? (syntax-e #'name)))
  >         (let-values ([(before after)
  >                       (split-at-dot (syntax-e #'name))])
  >           (with-syntax ([var (datum->syntax-object #'stx before)]
  >                         [acc (datum->syntax-object #'stx after)])
  >             #'(dot var acc)))]
  >        [(_ . name)
  >         #'(#%top . name)])))
  >
  >
  >
  > (require dot)
  > (define-struct color (r g b) (make-inspector))
  >
  > (define-accessor r color-r)
  > (define-accessor g color-g)
  > (define-accessor b color-b)
  >
  > (define a (make-color 1 2 3))
  > a.r
  > a.g
  > a.b
  >
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  >


  -- 
  sam th
  samth at ccs.neu.edu
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