prompt-dir calls the function "dir" (in dir.e")
Then you can use a reg-ex replace to eliminate all but the filename.
#include "slick.sh"
_command my_dir() name_info(','VSARG2_MARK|VSARG2_REQUIRES_EDITORCTL)
{
_macro('R',1);
dir("<"); // The "<" argument tells dir to prompt the user.
clear_highlights();
replace_buffer_text('^[> ] *([^ \t]+ +){4,4}(.*)$',"LIP*","$2",'0','0','0','0','0','0','1');
}