Classes in Mozart lang. Here we define `NewCounter` class and two objects named `Ctr1` and `Ctr2`.

classes.ozf

declare
fun {NewCounter}
C Bump Read in
   C = {NewCell 0}

   fun {Bump}
      C := @C + 1
      @C
   end

   fun {Read}
      @C
   end

   counter(bump:Bump read: Read)
end

declare
Ctr1={NewCounter}
Ctr2={NewCounter}
{Show Ctr1}
{Show {Ctr1.bump}}
{Show {Ctr2.bump}}
{Show {Ctr2.bump}}
{Show {Ctr2.bump}}