Is it possible that you missed out on #%top-interaction? http://docs.racket-lang.org/reference/__top-interaction.html?q=%23%25top#(form._((lib._racket/private/base..rkt)._~23~25top-interaction))
On May 29, 2012, at 7:44 PM, Nick Sivo wrote: > Hi, > > I'm trying to implement arc as a racket language extension. To become > familiar with racket's reader infrastructure, I thought I'd start with > something simple: > > ================== > kogir/arc/lang/reader.rkt: > ================== > #lang s-exp syntax/module-reader > (planet kogir/arc/language) > #:wrapper1 arc-read-wrapper > > (require (planet kogir/arc/reader)) > > ============== > kogir/arc/reader.rkt: > ============== > #lang racket/base > > (provide make-arc-readtable > arc-read-wrapper) > > (define (read-square-brackets ch port src line col pos) > (datum->syntax > #f > `(lambda (_) > ,(read-syntax/recursive src port #\[ #f)) > (let-values ([(l c p) (port-next-location port)]) > (list src line col pos (and pos (- p pos)))))) > > (define (make-arc-readtable) > (make-readtable (current-readtable) > #\[ 'terminating-macro read-square-brackets)) > > (define (arc-read-wrapper thunk read-syntax) > (parameterize ([current-readtable (make-arc-readtable)]) > (thunk))) > > ================ > kogir/arc/language.rkt: > ================ > #lang racket > > (provide (all-defined-out) > (all-from-out racket)) > > I expected it to give me a language very similar to racket, but with > arc's [ _ ] lambda syntax sugar: > [+ _ 1] => (lambda (_) (+ _ 1)) > > When I test in Dr. Racket, it works for reading files, but not in the > interaction window: > > ====== > test.arc: > ====== > #lang planet kogir/arc > > (define test [+ _ 1]) > > --------------------------------------------------------------------------------------- > > Welcome to DrRacket, version 5.2.1 [3m]. > Language: planet kogir/arc [custom]; memory limit: 128 MB. >> test > #<procedure:test> >> (test 1) > 2 >> [+ _ 1] > . _: wildcard not allowed as an expression in: _ > > What pieces am I missing to make the Dr. Racket interaction window > support the new syntax? > > Also, is it correct in kogir/arc/reader.rkt to use > `(lambda (_) > ,(read-syntax/recursive src port #\[ #f) > or should I use > #`(lambda (_) > #,(read-syntax/recursive src port #\[ #f) > > Both appear to work? > > Any pointers you might have would be awesome. I apologize in advance > if I missed something obvious. > > Thanks, > Nick > ____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
