On 8/30/16 Aug 30 -3:46 PM, 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, and relative pathnames have their own problems. The unix way of solving it is to transform relative pathnames with "$PWD/pathname" but I don't believe there is a builtin facility for doing the equivalent in common lisp, nor did I find one in a quick look throug uiop/pathname.
There is a method for doing this, but it's done through *default-pathname-defaults*
The problem is that the Unix way relies on the current working directory, but *default-pathname-defaults* is populated in a domain-dependent way.
Rant: As with non-CL software, it's amazing how many people assume that you will be running their software in the way they do, typically from the directory where the code is located. I cannot tell you how much aggregate time I have spent over the years hardening other people's software against violations of this assumption. Please folks, remember that even *I* may not know the working directory of my SLIME instance, so *you* cannot count on it!