[racket] examples of hooking a #lang into DrRacket?

Yeah: I think that it is safe to say at this point that pollen doesn't need
to change. Either read-language's docs (and various places in DrRacket and
libraries) need to change or read-language needs to change and either way
pollen will work afterwards.

My guess is that your language is the only one that doesn't define a
get-info function itself but I can't check that theory right now.

You can probably make pollen work now by supplying a get-info proc that
always returns the default value. (See the third and subsequent paragraphs
here:
http://docs.racket-lang.org/reference/Reading.html?q=read-language#%28def._%28%28quote._~23~25kernel%29._read-language%29%29
).

Robby

On Monday, July 21, 2014, Matthew Butterick <mb at mbtype.com> wrote:

> > It appears that read-language can return #f and what DrRacket does in
> > that case appears to be what you're seeing. Is that what you're
> > getting?
>
> Your theory seems correct. Yes, Pollen is the only #lang returning #f for
> read-language, e.g.:
>
> #lang racket/base
> (map
>  (λ(lang) (read-language (open-input-string (format "#lang ~a" lang))))
>     '(racket racket/base scratchy scribble/manual scribble/text rackjure
> pollen))
>
> '(#<procedure:language-info>
>   #<procedure:language-info>
>   #<procedure:...atchy/reader.rkt:26:2>
>   #<procedure:language-info>
>   #<procedure:language-info>
>   #<procedure:language-info>
>   #f)
>
>
> Moreover, if I use your main.rkt, it triggers the same problem in DrRacket
> (#lang line is red, no toolbar buttons)
>
> But beyond the issue of whether the docs or DrRacket is doing the right
> thing with the #f value, I'm unclear why Pollen is returning #f for
> read-language. One possibly unorthodox thing I'm doing here is that my
> #lang files rely on macro expansion. For instance, here's Pollen's main.rkt:
>
>
> #lang racket/base
> (require pollen/main-base)
> (define+provide-module-begin-in-mode world:mode-preproc)
>
> (module reader racket/base
>   (require pollen/reader-base)
>   (define+provide-reader-in-mode world:mode-auto))
>
>
> ... where `define+provide-module-begin-in-mode` is a macro that creates
> the #%module-begin macro, and `define+provide-reader-in-mode` is a macro
> that creates the reader.
>
> This doesn't bother DrRacket when the file is being run, but perhaps this
> approach is incompatible with either read-language, or DrRacket's #lang
> validation?
>
>
>
>
>
> On Jul 20, 2014, at 4:50 PM, Robby Findler <robby at eecs.northwestern.edu
> <javascript:;>> wrote:
>
> > It appears that read-language can return #f and what DrRacket does in
> > that case appears to be what you're seeing. Is that what you're
> > getting?
> >
> > The docs say that read-language never returns #f (presumably it is
> > allowed to return #f when fail-thunk returns #f, but the relevant
> > fail-thunk here doesn't return #f) so I'm not sure if that's a docs
> > bug, in which case I should change drracket to cope with it or an
> > implementation bug.
> >
> > But if I create a pollen directory, use 'rack pkg --link pollen' to
> > set it up and then put main.rkt with this content:
> >
> > #lang racket/base
> > (module reader racket/base (provide read-syntax)
> >  (define (read-syntax a b)
> >     #'(module m racket/base)))
> >
> > then I see this:
> >
> > $  racket
> > Welcome to Racket v6.1.0.3.
> >> (read-language (open-input-string "#lang pollen"))
> > #f
> >
> >
> > Robby
>
>
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