how to get a directory's "full" name?

[Robert P. J. Day]

  as part of my multi-arch build, i need to convert a (probably)
relative directory name to its full name.  that is, if someone refers
to "..", i need to get the full directory name of ".."

  this "function" seems to work:

real-dir = $(shell cd ${1} ; echo $${PWD})

cd to arg, then echo full dir name.  is there a simpler or built-in
way that's better?

rday