anchor.diff:    final Annotator annotator;
     ImportTable importTable;
     int indentation = 0;
  +  int column = 0;
   
     static int SPACE = 0;
     static int WORD = 1;
  
positive.code:   }
  
    visitBlockExpression(BlockExpression node) {
      writeWord('do:');
      writeNode(node.body);
      writeWord('done:');
      writeExpression(node.value);
    }
  
    defaultExpression(Expression node) {
  
negative.code: 
    void write(String string) {
      sink.write(string);
      column += string.length;
    }
  
    void writeSpace([String string = ' ']) {
  