Oops. It's not NAME that's the problem. It's #,my-read-stx that needs to change to (quote #,my-read-stx) instead.
Carl Eastlund On Tue, Aug 30, 2011 at 1:41 PM, Carl Eastlund <c...@ccs.neu.edu> wrote: > Just put an explicit "quote" form around it. Replace NAME with (quote > NAME) in the template. > > Right now there is no form to tell the expander how to expand NAME. > So the expander looks at the lexical context to see "how do I expand > this form". But NAME did not come from a lexical context, so it has > none. You don't really want to give it some, either -- it's not a > program, it's data. Wrapping it with quote tells the expander what it > needs to know via the context on the identifier "quote", and NAME can > thus stay as data without lexical context. > > Carl Eastlund > > On Tue, Aug 30, 2011 at 6:42 AM, Neil Van Dyke <n...@neilvandyke.org> wrote: >> I'm getting this error in some code with a macro transformer that produces >> syntax that includes some bits of child syntax that are sourced via >> "read-syntax". >> >> The below example demonstrates. >> >> Assuming that I really do want to use "read-syntax", how do I do this >> properly? (I assume that proper is not losing the "#%datum" by something >> like "(quasisyntax/loc stx #,(syntax->datum stx))".) >> >> >> #lang racket/base >> >> (require (for-syntax racket/base) ;; necessary >> (for-template racket/base) ;; doesn't help #%datum problem >> (for-label racket/base) ;; doesn't help #%datum problem >> ) >> >> (define-syntax (my-macro stx) >> (syntax-case stx () >> ((_ NAME) (let ((my-read-stx (read-syntax "my-sourcename" >> (open-input-string >> "\"hello\"")))) >> (quasisyntax/loc stx >> (string-append "Well, " #,my-read-stx ", " NAME "!")))))) >> >> (my-macro "yourname") >> ;;=exception=> compile: bad syntax; literal data is not allowed, because no >> #%datum syntax transformer is bound in: "hello" >> >> >> -- >> http://www.neilvandyke.org/ _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
