Jens Axel Soegaard's infix package does something similar. It solves part of this problem by using at-exp for longer strings, instead of using here strings. Because of that, it can tell the difference by using the `'scribble` syntax property that at-exp puts there.
I'm not sure whether a similar syntax property exists for here strings. Would that (at least partially) solve your problem? The place in the source where the infix package does this is here: https://github.com/soegaard/infix/blob/master/infix/main.rkt#L50 (let* ([from-at? (syntax-property stx 'scribble)] [offset (if from-at? 0 1)] ...) ...) Based on that syntax property, it defines the `offset` identifier as either `0` or `1`, and adds that to the `col` and `pos`. Although, much like your `(parse "'Hello\", said John")` example, that isn't quite sufficient, because it shows the wrong source location for things like this: #lang at-exp racket/base (require infix) (define x0 0) (define v 5) (define dt 1) @${x@"0" + v*dt} The sources for the `v` and the `dt` are 3 characters behind where they should be because the @"0" was automatically merged with the string. (Direct string escapes are handled specially.) If you want more thorough source locations within strings, you probably have to do more work than that, for all the cases of string escapes that you want to handle. Infix package docs: http://docs.racket-lang.org/infix-manual/index.html Infix package source: https://github.com/soegaard/infix/tree/master > On Apr 20, 2016, at 5:31 AM, Tim Brown <tim.br...@cityc.co.uk> wrote: > > Folks, > > I am writing a parser that will eventually take a string syntax object > to parse. I want to report errors where they are in the source file; > and with port-count-lines, and a bit of basic arithmetic, I should be > able to do this trivially. Except... for simple tests I will be using > quoted strings; but in anger, I will be using here strings. > > ;; --------------------------------------------------------------------- > #lang racket > (define-syntax (wheres-my-string stx) > (syntax-case stx () > [(_ s) > (eprintf "col: ~a span: ~a (string-length ~a) ~s~%" > (syntax-column #'s) > (syntax-span #'s) > (string-length (syntax-e #'s)) > #'s) > #'s])) > > > (wheres-my-string "abc") > > (wheres-my-string #<<$ > abc > $ > ) > ;; --------------------------------------------------------------------- > > My stderr output is: > col: 18 span: 5 (string-length 3) #<syntax:...> > col: 18 span: 10 (string-length 3) #<syntax:...> > > The syntax objects, when printed in DrRacket don’t have anything more > to distinguish an ordinary string from an inline string. > > Aside from (- span string-length) being 2 or >= 7, is there any better > way to identify the here string? > > Thanks, > > Tim > > PS: Ow, I’ve just thought; I’ve got a similar problem with: > > (parse "'Hello\", said John") > > and its #\\ quoting. Does anyone have any ideas about this > > -- > Tim Brown CEng MBCS <tim.br...@cityc.co.uk> > ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ > City Computing Limited · www.cityc.co.uk > City House · Sutton Park Rd · Sutton · Surrey · SM1 2AE · GB > T:+44 20 8770 2110 · F:+44 20 8770 2130 > ──────────────────────────────────────────────────────────────────────── > City Computing Limited registered in London No:1767817. > Registered Office: City House, Sutton Park Road, Sutton, Surrey, SM1 2AE > VAT No: GB 918 4680 96 -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
