%!PS

% begin included library code
% see https://github.com/Firedrake/postscript-libraries/
/test.start {
    print (:) print
    /test.pass 0 def
    /test.count 0 def
} bind def

/jd2ymd {
    15 dict begin
    /y 4716 def
    /v 3 def
    /j 1401 def
    /u 5 def
    /m 2 def
    /s 153 def
    /n 12 def
    /w 2 def
    /r 4 def
    /B 274277 def
    /p 1461 def
    /C -38 def
    dup
    4 mul B add 146097 idiv 3 mul 4 idiv C add j add add /f exch def
    r f mul v add /e exch def
    e p mod r idiv u mul w add /h exch def
    /day h s mod u idiv 1 add def
    /month h s idiv m add n mod 1 add def
    /year e p idiv y sub n m add month sub n idiv add def
    [ year month day ]
    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

/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

/strconcat % (a) (b) -> (ab)  
{ exch dup length
  2 index length add string
  dup dup 4 2 roll copy length
  4 -1 roll putinterval
} bind def

/deepeq {
    2 dict begin
    /a exch def
    /b exch def
    a type b type eq {
        a type /dicttype eq {
            a length b length eq {
                <<
                    a {
                        pop
                        true
                    } forall
                    b {
                        pop
                        true
                    } forall
                >>
                true exch
                {
                    pop
                    dup a exch known {
                        dup b exch known {
                            dup a exch get exch b exch get deepeq not {
                                pop false
                            } if
                        } {
                            false
                        } ifelse
                    } {
                        false
                    } ifelse
                } forall
            } {
                false
            } ifelse
        } {
            a type dup /arraytype eq exch /stringtype eq or {
                a length b length eq {
                    true
                    0 1 a length 1 sub {
                        dup a exch get exch b exch get deepeq not {
                            pop false
                            exit
                        } if
                    } for
                } {
                    false
                } ifelse
            } {
                a b eq
            } ifelse
        } ifelse
    } {
        false
    } ifelse
    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

/ymd2jd {
    4 dict begin
    aload pop
    /d exch def
    /m exch def
    /y exch def
    /mn m 14 sub 12 idiv def
    y 4800 add mn add 1461 mul 4 idiv
    mn 12 mul neg 2 sub m add 367 mul 12 idiv add
    y 4900 add mn add 100 idiv 3 mul 4 idiv sub
    d add
    32075 sub
    end
} bind def

/jd2dow {
    1 add 7 mod 
} bind def


% end included library code

/lastsunday {
    3 dict begin
    /year exch def
    [
        2 1 13 {
            /month exch def
            month 13 eq {
                /month month 12 sub def
                /year year 1 add def
            } if
            [ year month 1 ] ymd2jd 1 sub dup jd2dow sub jd2ymd /od exch def
            [
                od 0 get (....) cvs
                od 1 get dup 10 lt {
                    (.) cvs (0) exch strconcat
                } {
                    (..) cvs
                } ifelse
                od 2 get (..) cvs
            ] (-) strjoin
        } for
    ]
    end
} bind def

(lastsunday) test.start
2022 lastsunday
[ (2022-01-30) (2022-02-27) (2022-03-27) (2022-04-24) (2022-05-29)
  (2022-06-26) (2022-07-31) (2022-08-28) (2022-09-25) (2022-10-30)
  (2022-11-27) (2022-12-25) ]
deepeq test
test.end