Save as Text Doc "boo.txt" -> saved as boo.txt       /\.txt\z/==1
Save as Text Doc "boo"     -> saved as boo.txt       /\.txt\z/==0
Save as Text Doc "boo."    -> saved as boo..txt      /\.txt\z/==0
Save as Text Doc "boo.pl"  -> saved as boo.pl.txt    /\.txt\z/==0
Save as Text Doc "boo. pl" -> saved as boo. pl.txt   /\.txt\z/==0

Save as All Files "boo.txt" -> saved as boo.txt      '.txt' ne ''
Save as All Files "boo"     -> saved as boo.txt      ''     eq ''
Save as All Files "boo."    -> saved as boo.         '.'    ne ''
Save as All Files "boo.pl"  -> saved as boo.pl       '.pl'  ne ''
Save as All Files "boo. pl" -> saved as boo. pl.txt  ''     eq ''