%!PS

% begin included library code
% see https://codeberg.org/Firedrake/postscript-libraries/
/test.end {
    ( ) print
    test.count 0 gt {
        (Passed ) print
        test.pass (...) cvs print
        (/) print
        test.count (...) cvs print
        ( \() print
        test.pass 100 mul test.count idiv (...) cvs print
        (%\)) print
        (\r\n) print
    } if
} bind def

/test {
    /test.count test.count 1 add def
    {
        /test.pass test.pass 1 add def
    } {
        ( ) print
        test.count (....) cvs print
        (-fail) print
    } ifelse
} bind def

/test.start {
    print (:) print
    /test.pass 0 def
    /test.count 0 def
} bind def


% end included library code

/threepower {
    0 dict begin
    /n exch def
    n 0 eq {
        false
    } {
        /n n abs def
        /lo 1 def
        /hi n 2 idiv def
        {
            /t lo hi add 2 idiv def
            /c t dup dup mul mul def
            c n eq {
                true
                exit
            } if
            lo t eq {
                false
                exit
            } if
            c n lt {
                /lo t def
            } {
                /hi t def
            } ifelse
        } loop
    } ifelse
    end
} bind def

(threepower) test.start
27 threepower test
0 threepower not test
6 threepower not test
test.end