Thanks, that makes sense. However, I tried doing this with a variable
defined within a program, but it doesn't work. I would like the user to
define their our `root` function to wrap everything, however, when I try to
access it with `syntax-local-introduce` it isn't found. I have:
(define-for-syntax md-module-begin
(syntax-parser
[(_ (expr1 ...))
#:with accumulated (syntax-local-introduce (datum->syntax #f
'accumulated))
#:with root (syntax-local-introduce (datum->syntax #f 'root))
#`(wrapping-modbeg (define accumulated "")
expr1 ...
(define doc (root (parse-markdown accumulated)))
(provide doc)
(print doc))]))
For my module begin and:
**asdf**
@"asdf2"
@(define (root x . y) '(test "asdf"))
@(define x 5)
x Is @x
@(string-append "test " "string")
<asdf>123</asdf>
as an example program. However, it complains that `root` is undefined.
On Friday, August 17, 2018 at 9:51:38 PM UTC-6, Philip McGrath wrote:
>
> The error is `set!` reporting that `doc` is undefined, because the `doc`
> identifier from `md-module-begin` is introduced hygienically. Also, I
> believe your pattern for `md-module-begin` has an extra set of parentheses.
> Here is a working version:
>
> #lang racket/base
>
> #lang racket/base
>
> (module lang racket/base
> (require syntax/wrap-modbeg
> (for-syntax racket/base
> syntax/parse))
> (provide (except-out (all-from-out racket/base)
> #%module-begin)
> (rename-out [md-module-begin #%module-begin]))
> (define-syntax handle
> (syntax-parser
> [(_ b:expr)
> #:with doc (syntax-local-introduce (datum->syntax #f 'doc))
> #`(set! doc (string-append doc b))]))
> (define-syntax wrapping-modbeg
> (make-wrapping-module-begin #'handle))
> (define-syntax md-module-begin
> (syntax-parser
> [(_ expr1 ...)
> #:with doc (syntax-local-introduce (datum->syntax #f 'doc))
> #'(wrapping-modbeg (define doc "")
> expr1 ...)])))
>
> (module example (submod ".." lang)
> (provide doc)
> "Example")
>
> (require (submod "." example))
>
> doc
>
>
>
> -Philip
>
> On Sat, Aug 18, 2018 at 3:36 AM, Vityou <zle...@gmail.com <javascript:>>
> wrote:
>
>> Stupid question, but how would I saving them in a global variable? So
>> far I have this:
>>
>> (define-syntax handle
>> (syntax-parser
>> [(_ b:expr) #`(set! #,(syntax-local-introduce (datum->syntax #f
>> 'doc)) (string-append #,(syntax-local-introduce (datum->syntax #f 'doc))
>> b))]))
>>
>> (define-syntax wrapping-modbeg
>> (make-wrapping-module-begin #'handle))
>>
>> (define-syntax md-module-begin
>> (syntax-parser
>> [(_ (expr1 ...)) #'(wrapping-modbeg (define doc "")
>> expr1 ...)]))
>>
>> However, it complains that `set!` isn't defined. I thought it would be
>> defined since my module provides `racket/base`.
>>
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>
>
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