If you look in the Typed Racket implementation, you'll see lots phase-1 only uses of syntax-parse. Sam <div class="gmail_quote">On Sep 24, 2013 3:21 PM, "Nick Sivo" <<a href="mailto:nicksivo@gmail.com">nicksivo@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Why doesn't syntax/parse just provide everything at phases 0 and 1 like the module 'sp below: (module sp racket/base (require syntax/parse (for-syntax syntax/parse)) (provide (all-from-out syntax/parse) (for-syntax (all-from-out syntax/parse)))) (require 'sp) (define-syntax (mylet stx) (syntax-parse stx [(_ ([var-id rhs-expr] ...) body ...+) #'((lambda (var-id ...) body ...) rhs-expr ...)])) I've not done as much Racket programming as many of you, but I've yet to want syntax/parse in only phase 0. -Nick On Tue, Sep 24, 2013 at 10:21 AM, Laurent <<a href="mailto:laurent.orseau@gmail.com">laurent.orseau@gmail.com</a>> wrote: > This is a quite common pitfall into which I have myself fallen a few times, > and I guess it's not the last time. > > How much work would be required to prevent people from falling into it ever > again? > Maybe saying so in the docs at the right place wouldn't hurt, but people may > still miss it. > Maybe making the error message more specific like "Did you forget to > (require (for-syntax syntax/parse)) ?" ? Or is it too specific? > Or pushing the idea further (and requiring more work, obviously), Racket's > errors could propose a list of packages where the unknown identifier can be > found, along with the require phase? Is xref able to do that currently? > > Laurent > > > > On Tue, Sep 24, 2013 at 6:20 PM, Stephen Chang <<a href="mailto:stchang@ccs.neu.edu">stchang@ccs.neu.edu</a>> wrote: >> >> You need (require (for-syntax syntax/parse)) because you are using it >> inside a define-syntax. >> >> On Sep 24, 2013 11:56 AM, "Konrad Hinsen" <<a href="mailto:konrad.hinsen@fastmail.net">konrad.hinsen@fastmail.net</a>> >> wrote: >>> >>> Hi everyone, >>> >>> I am trying to learn about syntax-parse, starting with the introduction >>> of the "Syntax" documentation. >>> >>> Unfortunately, the very first example given for the use of syntax-parse >>> doesn't work in my Racket installation: >>> >>> Welcome to Racket v5.90.0.9. >>> racket@> (require syntax/parse) >>> racket@> (define-syntax (mylet stx) >>> (syntax-parse stx >>> [(_ ([var-id rhs-expr] ...) body ...+) >>> #'((lambda (var-id ...) body ...) rhs-expr ...)])) >>> stdin::277: _: wildcard not allowed as an expression >>> in: (_ ((var-id rhs-expr) ...) body ...+) >>> errortrace...: >>> context...: >>> try-next >>> >>> /Users/hinsen/Development/racket/pkgs/errortrace-pkgs/errortrace-lib/errortrace/errortrace-lib.rkt:480:4 >>> >>> /Users/hinsen/Applications/Racket/collects/racket/private/misc.rkt:87:7 >>> >>> I tried replacing the wildcard by "mylet", but that only leads to another >>> error >>> message: >>> >>> racket@> (define-syntax (mylet stx) >>> (syntax-parse stx >>> [(mylet ([var-id rhs-expr] ...) body ...+) >>> #'((lambda (var-id ...) body ...) rhs-expr ...)])) >>> stdin::842: ...: ellipses not allowed as an expression >>> in: ... >>> errortrace...: >>> context...: >>> try-next >>> >>> /Users/hinsen/Development/racket/pkgs/errortrace-pkgs/errortrace-lib/errortrace/errortrace-lib.rkt:480:4 >>> >>> /Users/hinsen/Applications/Racket/collects/racket/private/misc.rkt:87:7 >>> >>> Am I doing something wrong here? Or are the examples obsolete? >>> >>> Konrad. >>> ____________________ >>> Racket Users list: >>> <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> >> >> >> ____________________ >> Racket Users list: >> <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> >> > > > ____________________ > Racket Users list: > <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> > ____________________ Racket Users list: <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> </blockquote></div>