[asdf-devel] asdf output locations --- content files

[Tobias C. Rittweiler]

Robert Goldman writes:

> ....
>> 
>>> In the spirit of ASDF, we should be writing output-files methods and
>>> then allowing your code to shuffle them, but that use-case seems to
>>> break down a bit here.
>>>
>>> Consider providing an asdf system definition for a web site.  You want
>>> to specify the relative location of the content files, which may be
>>> generated by asdf operations (e.g., my parenscript example).  Those
>>> content files must be findable by the code in your system.  So this
>>> seems like a case where the "let the end user decide where to put the
>>> output files" breaks down....  Hm.  Needs more thought.  These web
>>> content files are a case where the code/data distinction is not so
>>> clear, and ASDF has not handled data files well (indeed, by
>>> unpredictably relocating code files, it has broken our ability to find
>>> data files using *load-truename*).
>>>
>> I don't have a clear solution for that problem at this point.
>> If anyone has one, I'm curious.
>> 
>> ASDF has no notion of "installed file".
>
> Agreed, and this can be a real nuisance if your system carries data
> along with it.
>
> I thought I would mention this now.  If we're reforming file writing, we
> might want to try to pick off this problem as well.
>
> The web application is a plausible one as is, for example, a graphical
> app that has image files contained with it.
>
> Using *load-truename* to find such files is, as I mentioned earlier,
> broken by use of A-B-L or any other code that wrangles the output files
> of the compile-op.
>
> What I typically do is something unpleasant like this (from memory;
> possibly slightly inaccurate):
>
> 1.  In the asdf system definition file, do something like this:
>
> (defparameter cl-user::*<sysname>-root-directory*
>   (merge-pathnames (make-pathname :type :unspecific :name :unspecific)
>                    *load-truename*))
> ;; use cl-user because you don't have access to the package(s) in the
> ;; as yet not loaded system...
>
> 2.  In the loaded files at some point
>
> (with-open-file (str (merge-pathnames "imagefile.png"
>                                       cl-user::*<sysname>-root-directory*))
>   ....)
>
> I'd love to see a clean way to avoid this....

I do not understand the issue at hand -- just want provide a comment on
the side:

Instead of *LOAD-TRUENAME* in the .asd file, you could probably get away
with using *COMPILE-FILE-PATHNAME*, say, in the your package.lisp? Which
would not be wrangled by ASDF-Binary-Locations and consorts. (It also
solves the package problem.)

  -T.