%!PS

% begin included library code
% see https://codeberg.org/Firedrake/postscript-libraries/
/s2a {
    [ exch { } forall ]
} bind def

/strconcat % (a) (b) -> (ab)  
{
    [
        3 -1 roll
        s2a aload length
        2 add -1 roll
        s2a aload pop
    ] a2s
} bind def

/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

/a2s {
    2 dict begin
    /i exch def
    i length dup string /o exch def
    1 sub 0 exch 1 exch {
        dup i 3 -1 roll get o 3 1 roll put
    } for
    o
    end
} 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

/enumerate.array {
    1 dict begin
    /a exch def
    [
      0 1 a length 1 sub {
          [ exch dup a exch get ]
      } for
    ]
    end
} bind def

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

/strjoin % [(a) (b) (c)] (j) -> (ajbjc)
{
    3 dict begin
    /j exch def
    dup 0 get /out exch def
    /first true def
    {
        first {
            pop
            /first false def
        } {
            out j strconcat
            exch strconcat
            /out exch def
        } ifelse
    } forall
    out
    end
} bind def


% end included library code

/sortletters {
    0 dict begin
    /c exch def
    /a exch def
    /out a length array def
    a enumerate.array {
        aload pop
        /l exch def
        /i exch def
        out c i get 1 sub l put
    } forall
    out () strjoin
    end
} bind def

(sortletters) test.start
[(R) (E) (P) (L)] [3 2 1 4] sortletters (PERL) eq test
[(A) (U) (R) (K)] [2 4 1 3] sortletters (RAKU) eq test
[(O) (H) (Y) (N) (P) (T)] [5 4 2 6 1 3] sortletters (PYTHON) eq test
test.end