Andy Wingo <wi...@pobox.com> writes:
> Hi Neil,
>
> On Sat 14 Jan 2012 22:48, Neil Jerram <n...@ossau.homelinux.net> writes:
>
>> Andy Wingo <wi...@pobox.com> writes:
>>
>> Of the possibilities above, I think I prefer
>>
>>> (add-to-load-path (dirname (current-source-filename)))
>
> Done. Actually I called it "current-filename", so it would be:
>
> (add-to-load-path (dirname (current-filename)))
>
> Feedback is very welcome -- especially timely feedback; it would be nice
> to release on Monday or so. I'm attaching the patch (already committed)
> to make it easy for you :)
Thanks!
The patch works for me, although there are a couple of points that still
make it a bit fiddly to use in practice. It might be possible to
improve the first of those points, but I don't think anything can be
done about the second.
Thing 1 is that (current-filename) can return a relative filename, or a
filename with a "./" in its middle:
1.1: With a script called "affiche", with "#! /usr/bin/guile -s" and
which I invoke from the shell as "./affiche", (current-filename) gives
"/home/neil/q/SW/ossaulib/scripts/./affiche". So if I do (dirname
(dirname (current-filename)), intending to get the parent directory
"/home/neil/q/SW/ossaulib", I actually get
"/home/neil/q/SW/ossaulib/scripts".
1.2: If I encapsulate the load-path logic in a separate file called
"setup-load-path.scm", and take advantage of the fact that (include
"setup-load-path.scm") will find that file in the same directory as
"affiche", (current-filename) gives just "setup-load-path.scm", and
(dirname ...) on that won't give a useful result.
Both problems are solved by adding in a canonicalize-path call. Would
there be any downside from putting that inside current-filename, so that
current-filename always returns a canonical file name?
Alternatively, I think the use of canonicalize-path should be added into
the example in the manual.
Thing 2 is that it remains slightly inelegant to cater for both 1.8 and
2.0. I think the minimal complete solution is to write
(cond-expand (guile-2 (include "setup-load-path.scm"))
(else (load "setup-load-path.scm")))
at top level in every uninstalled script, and then something like
(cond-expand (guile-2
(add-to-load-path
(dirname
(dirname
(canonicalize-path (current-filename))))))
(else
;; Less elegant code for 1.8...
(let* ((bindir (dirname (car (command-line))))
(absdir (cond ((string=? bindir ".")
(getcwd))
((string-match "^/" bindir)
bindir)
(else
(in-vicinity (getcwd) bindir)))))
(set! %load-path (cons (in-vicinity absdir "..")
%load-path)))))
in setup-load-path.scm.
But without a time machine I don't think anything can be done to make
either of those fragments more concise.
I also had just one comment on the doc:
> @@ -814,9 +780,9 @@ change occurs at the right time.
> @defvar %load-hook
> A procedure to be called @code{(%load-hook @var{filename})} whenever a
> file is loaded, or @code{#f} for no such call. @code{%load-hook} is
> -used by all of the above loading functions (@code{load},
> -@code{load-path}, @code{primitive-load} and
> -@code{primitive-load-path}).
> +used by all of the loading functions (@code{load} and
> +@code{primitive-load}, and @code{load-path} and
> +@code{primitive-load-path} documented in the next section).
[...]
> +@deffn {Scheme Procedure} load-from-path filename
Is it 'load-path' or 'load-from-path'?
Regards,
Neil
