[racket] How `scribble` resolves relative paths

I made a rudimentary helper macro called `image/rp` that upgrades a relative path-string into a runtime path:

(define-syntax (image/rp stx)
  (syntax-case stx ()
    [(_ name) #'(image/rp name 1.0)]
    [(_ name scale) #'(begin
                        (define-runtime-path rp name)
                        (image rp #:scale scale))]))

Of course, the problem is that it disregards the interface for `image`, which includes keyword arguments.

Is there a standard idiom for matching keyword arguments with `syntax-case` ...

1) To capture all keyword arguments and pass them through unaltered?
2) To unpack keyword arguments, alter them, and reapply them?



On Sep 1, 2014, at 9:59 PM, Matthew Flatt <mflatt at cs.utah.edu> wrote:

> I think the docs are wrong. While `raco setup` does set the current
> directory, `scribble` does not.
> 
> It's better to use `define-runtime-path` instead of relying on the
> current directory, since that composes better.
> 
> At Mon, 1 Sep 2014 18:20:05 -0700, Matthew Butterick wrote:
>> I am confused by this statement in the docs vs. the actual behavior:
>> 
>> The docs for `image` say that "If path is a relative path, it is relative to 
>> the current directory, which is set by `raco setup` and `scribble` to the 
>> directory of the main document file." (I'm using `image` as an example but I've 
>> seen the same problem with CSS files.)
>> 
>> Suppose I have a project set up like this:
>> 
>> /project
>>    /scribblings
>>        main.scrbl
>>        sample.gif
>> 
>> And "main.scrbl" contains this:
>> 
>> #lang scribble/manual
>> @image["sample.gif"] 
>> 
>> If I do this:
>>> cd project
>>> cd scribblings
>>> scribble main.html
>> 
>> The HTML will render fine.
>> 
>> But if I do this:
>> 
>>> cd project
>>> scribble --dest-name doc scribblings/main.scrbl
>> 
>> I'll get this error:
>> 
>> open-input-file: cannot open input file
>>  path: /project/sample.gif
>> 
>> Thus, the relative path "sample.gif" is being resolved relative to the 
>> directory where I invoke the `scribble` command, not the "directory of the main 
>> document file", which in both cases seems like it should be  
>> /project/scribblings (i.e., the directory containing "main.scrbl").
>> 
>> What am I misunderstanding?
>> 
>> 
>> 
>> 
>> 
>> 
>> [1] 
>> http://docs.racket-lang.org/scribble/base.html?q=image#%28def._%28%28lib._scribb
>> le%2Fbase..rkt%29._image%29%29____________________
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