Be aware that the function will condition the path for you; do not do it yourself or you will have resulting errors.
Ex: that paths with spaces in them do NOT need the escaping slash
<?php
svn_ls('file://var/svn/myrepo/dirA/another dir'); /will work->happiness
svn_ls('file://var/svn/myrepo/dirA/another\ dir'); /will fail
?>
Warning: svn_ls(): svn error(s) occured 160013 (Filesystem has no item) URL 'file://var/svn/myrepo/dirA/another\ dir' non-existent in that revision in file.php on line 42