void->int filter Generate{
  int x=0;				//Note that native filters can have state.
  work push 1{
	push(x);
	x = x+1;
  }
}

int->void filter Read{
  work pop 1{    
	 print( pop() );
  } 
}


bit->bit filter BoolFilter{
  work push 2 pop 4{		
    push( ( (peek(1) & peek(2) ) ^ (peek(0) | peek(3))  ) );
    push( ( (peek(2) | peek(3)) & (1^(peek(2) & peek(1))) ) ); // note that 1 ^ x is equivalent to ! x
    for(int i=0; i<4; ++i) pop();
  }	
}


void->void pipeline BoolFilterPL{
  add Generate();

  add BoolFilter();

  add Read();
}