<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.6000.16414" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV>Hi Sam,</DIV> <DIV>Thanks for the tip, but it does not help.</DIV> <DIV>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.</DIV> <DIV>Jos</DIV> <DIV> </DIV> <DIV>(((((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"))))</DIV> <BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"> <DIV style="FONT: 10pt arial">----- Original Message ----- </DIV> <DIV style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">From: <A title=samth@ccs.neu.edu href="mailto:samth@ccs.neu.edu">Sam TH</A> </DIV> <DIV style="FONT: 10pt arial">To: <A title=jos.koot@telefonica.net href="mailto:jos.koot@telefonica.net">jos koot</A> </DIV> <DIV style="FONT: 10pt arial">Cc: <A title=plt-scheme@list.cs.brown.edu href="mailto:plt-scheme@list.cs.brown.edu">plt-scheme@list.cs.brown.edu</A> ; <A title=jensaxel@soegaard.net href="mailto:jensaxel@soegaard.net">Jens Axel Søgaard</A> </DIV> <DIV style="FONT: 10pt arial">Sent: Sunday, March 11, 2007 2:52 PM</DIV> <DIV style="FONT: 10pt arial">Subject: Re: [plt-scheme] Dot-notation for structure field access</DIV> <DIV> </DIV>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 <<A href="mailto:jos.koot@telefonica.net">jos.koot@telefonica.net</A>> 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: <A href="mailto:plt-scheme@list.cs.brown.edu">plt-scheme@list.cs.brown.edu</A> > 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 > > _________________________________________________ >   For list-related administrative tasks: >   <A href="http://list.cs.brown.edu/mailman/listinfo/plt-scheme">http://list.cs.brown.edu/mailman/listinfo/plt-scheme</A> > > _________________________________________________ >   For list-related administrative tasks: >   <A href="http://list.cs.brown.edu/mailman/listinfo/plt-scheme">http://list.cs.brown.edu/mailman/listinfo/plt-scheme</A> > > > -- sam th <A href="mailto:samth@ccs.neu.edu">samth@ccs.neu.edu</A> </BLOCKQUOTE></BODY></HTML>