%!PS

% begin included library code
% see https://codeberg.org/Firedrake/postscript-libraries/
/s2a {
    [ exch { } forall ]
} 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.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.start {
    print (:) print
    /test.pass 0 def
    /test.count 0 def
} 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

/reverse {
    1 dict begin
    dup length /l exch def
    [ exch
      aload pop
      2 1 l {
          -1 roll
      } for
    ]
    end
} bind def


% end included library code

/reverseprefix {
    /f exch def
    /a exch def
    /c a s2a def
    a f search {
        length /p exch def pop pop
        c 0 p 1 add getinterval reverse
        c exch 0 exch putinterval
    } {
        pop
    } ifelse
    c a2s
} bind def

(reverseprefix) test.start
(programming) (g) reverseprefix (gorpramming) eq test
(hello) (h) reverseprefix (hello) eq test
(abcdefghij) (h) reverseprefix (hgfedcbaij) eq test
(reverse) (s) reverseprefix (srevere) eq test
(perl) (r) reverseprefix (repl) eq test
test.end