public SignedNumberExpr(Sign sign, UNumericLiteral operand)
 {
     this.Comments = new Comments(2);
     this.Sign     = sign;
     this.Operand  = operand;
 }
 void IVisitor.Visit(UNumericLiteral literal)
 {
     this.ParentExists(literal);
 }
 internal SignedNumberExpr(Sign sign, UNumericLiteral operand, Comments comments)
 {
     this.Comments = comments;
     this.Sign     = sign;
     this.Operand  = operand;
 }