On 8/31/16 Aug 31 -11:43 AM, Robert Goldman wrote:
On 8/31/16 Aug 31 -11:26 AM, Kevin Layer wrote:
Jason Miller wrote:
On 09:48 Mon 29 Aug , Kevin Layer wrote:
I've avoided getting into this discussion, but I feel I need to ask: why use *load-truename* instead of *load-pathname*?
*load-truename* goes through symbolic links (even though the ANS says nothing about it, this is the behavior of implementations I know of) and that is almost always the wrong thing. GNU make doesn't do it, I don't see why ASDF should do it. A build system should never itself follow symlinks, because it defeats systems that have been in place for 30+ years: linked directories of binary files linking to a single source directory.
Somewhat off-topic, but I'll bite:
This is because *load-pathname* is likely to be a relative pathname, ..
This is certainly not true in Allegro. In lisps where it is true, it's easily fixable with (merge-pathnames *load-pathname*).
I suppose this is safe, but I always have an unpleasant feeling about using a function call like this that depends on the value of a special variable (*default-pathname-defaults*) that I don't control.
At any rate, we pretty much established that in an ASDF-loaded system, *load-pathname* is likely to be garbagy, because at load time it typically holds the pathname of the *RELOCATED* FASL file, which is of no use to anyone.
This issue just popped up on the LispWorks users group mailing list, so I took a few minutes to write a FAQ about it, and pushed it into the manual.
I have updated the manual version on the ASDF web page at common-lisp.net to hold the new version.
Comments welcome.