// class init:

FILES = [];
index = 0;
FILES[index] = void

// class functions:

func open(file, ...):
   ff = fopen(vargs(1), vargs(2))
   return ff
end

func close(file, ...):
   fclose(file)
   return file
end

func write(file, ...):
   fwrite(file, vargs(1))
   return file
end

// main class:

func file(op, ...):
   FILES[index] = op(FILES[index], vargs(1), vargs(2))
   return FILES[index]
end

// using the class

file(open, "1.txt", "w")
file(write, "file 1")
file(write, "\nA text.")
file(close)

// the index was 0, means we were manipulating FILES[0]
index = 1;
// now we are manipulating FILES[1]
file(open, "2.txt", "w")
file(write, "file 2")
file(write, "\nA text.")
file(close)