Small problem with XDG_DATA_DIRS and XDG_CONFIG_DIRS

[Behdad Esfahbod]

Hi,

The current spec by falling back on some const values when the
XDG_*_DIRS are not set or are empty, prevents one from prepending
(or appending) directories to them easily.  In other words, for
example, when I want to compile some applications under /opt, I
would put something like this in my .bashrc:


  PREFIX=/opt
  export PATH="$PREFIX/bin:$PATH"
  export LD_LIBRARY_PATH="$PREFIX/lib:$LD_LIBRARY_PATH"
  export CPPFLAGS="-I$PREFIX/include $CPPFLAGS"
  export CFLAGS="-I$PREFIX/include $CFLAGS"
  export CXXFLAGS="-I$PREFIX/include $CXXFLAGS"
  export LDFLAGS="-L$PREFIX/lib $LDFLAGS"
  export PKG_CONFIG_PATH="$PREFIX/lib/pkgconfig:$PKG_CONFIG_PATH"
  export MANPATH="$PREFIX/man:$MANPATH"
  export PYTHONPATH="$PREFIX/lib/python:$PREFIX/lib/python2.3/site-packages:$PYTHONPATH"
  export PERL5LIB="$PREFIX/lib/perl5/site_perl:$PERL5LIB"
  export CLASSPATH=".:$PREFIX/lib/java:$CLASSPATH"
  export ACLOCAL_FLAGS="-I $PREFIX/share/aclocal $ACLOCAL_FLAGS"
  export ACLOCAL_AMFLAGS="-I $PREFIX/share/aclocal $ACLOCAL_AMFLAGS"
  ...

But this can't be done with XDG_*_DIRS, since as soon as you set
it, you are losing the default values.  So for a couple months
I've been doing:

  export XDG_DATA_DIRS="$PREFIX/share:$XDG_DATA_DIRS"

And wondering why my menus are lost!

I can think of one solution, but it has its own problem:  Treat
any empty component of the list as the default values.  Then
for example "/opt/share:" means "/opt/share" followed by the
default list.

Perhaps not the biggest problem and not the best solution, but
worth discussion IMHO.

--behdad