%!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

/set.difference {
    4 dict begin
    /s 0 dict def
    /b exch def
    /a exch def
    a keys {
        /k exch def
        b k known not {
            s k true put
        } if
    } forall
    s
    end
} bind def

/keys { % dict -> array of dict keys
    [ exch
      {
          pop
      } forall
    ]
} bind def

/map { % array proc -> array
    2 dict begin
    /p exch def
    [ exch
      {
          p
      } forall
    ]
    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

/toset { % array -> dict of (value, true)
    << exch
       {
           true
       } forall
    >>
} bind def

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


% end included library code

/noconnection {
    0 dict begin
    /a exch def
    /os a { 0 get } map toset def
    /is a { 1 get } map toset def
    is os set.difference keys 0 get
    end
} bind def

(noconnection) test.start
[[(B) (C)] [(D) (B)] [(C) (A)]] noconnection (A) eq test
[[(A) (Z)]] noconnection (Z) eq test
test.end