On Thursday, March 15, 2012 5:25:13 PM UTC+1, Nils Bruin wrote: > > On Mar 15, 12:21 am, "syd.lavas...@gmail.com" <syd.lavas...@gmail.com> > wrote: > > The problem is that my home directory is: > > > > /files3/home/sahosse/ > > > > but I only have execution permission to the directory "home": > > I confirm: > > $ mkdir /tmp/test > $ chmod a-r /tmp/test > $ mkdir /tmp/test/a > $ touch /tmp/test/a/b > $ ls /tmp/test/a/* > /tmp/test/a/b > > $ ecl > ECL (Embeddable Common-Lisp) 11.1.1 > [...] > > (directory "/tmp/test/a/*") > > NIL > > (quit) > $ chmod u+r /tmp/test > $ ecl > ECL (Embeddable Common-Lisp) 11.1.1 > [...] > > (directory "/tmp/test/a/*") > > (#P"/tmp/test/a/b") > > so, changing read permissions on a directory higher up in the tree > makes everything below not reachable for "directory". The same problem > arises for multi-level wildcards in the shell, i.e., "ls /tmp/test/*/ > *" can't find /tmp/test/a/b either if test is not readable. I guess > ECL uses the same code for wildcards as it uses for specified path > components. >
This is now fixed in CVS. It is a question of semantics not of good or "poor" implementations, as described above. I interpreted that the _whole_ of the argument to DIRECTORY is to be processed as a pattern matching pathname. Indeed, contrary to what Unix users would expect, we cannot optimize a directory to "/foo/faa/fee/*" jumping directly into the last component because we have to find out truenames -- in other words, if "faa" or "foo" are actually links, we have to traverse them and substitute the appropriate parts of the pathname by their content (See http://clhs.lisp.se/Body/f_dir.htm and http://clhs.lisp.se/Body/26_glo_t.htm#truename). I have modified the implementation of DIRECTORY to read as follows (sketch, the actual implementation is more complicated) * Loop D over directory components ** If D is not a wildcard component *** Enter D *** If D is a link, replace by value ** Else *** List directory content *** Collect components that match D *** Recursively process each component ** End If * Formerly the first "If" was not present. -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
