anchor.diff:  	tryPathExtension("../../../././././foo.bmp", expect: "bmp", withDot: ".bmp");
   }
   
  -unittest std.io.path.filename
  -{
  +unittest std.io.path.filename {
   	var tryPathFilename = func (cref path: string, cref expect: string) {
   		ref got = std.io.path.filename(path);
   		if got != expect then {
  
positive.code: 		var has   = std.io.path.hasExtension(file);
  		var dot   = std.io.path.extension(file);
  		var nodot = std.io.path.extension(file, withDot: false);
  
  		if has != expectHas or dot != expectDot or nodot != expectNoDot then {
  			printerr("error: fail '\(file)'\n");
  			printerr("       got: has: '\(has)', ext: '\(dot)', nodot: '\(nodot)'\n");
  
negative.code: 	tryPathParentFolder("", expect: "");
  }
  
  unittest std.io.path.stem {
  	var tryPathStem = func (cref path: string, cref expect: string) {
  		ref got = std.io.path.stem(path);
  		if got != expect then {
  