code: func (v *printVisitor) VisitHash(node *Hash) interface{} {
  	v.str("HASH{")
  
  	for i, p := range node.Pairs {
  		if i > 0 {
  			v.str(", ")
  		}
  		p.Accept(v)
  	}
  
  	v.str("}")
  
  	return nil
  }
docs: // Miscellaneous
  // VisitHash implements corresponding Visitor interface method