99                 self.wtr.write_str("[")?;  in visit_pre()
105                         self.wtr.write_str("-")?;  in visit_pre()
109                 self.wtr.write_str("]")?;  in visit_pre()
112                 self.wtr.write_str("(?-u:[")?;  in visit_pre()
118                         self.wtr.write_str("-")?;  in visit_pre()
122                 self.wtr.write_str("])")?;  in visit_pre()
125                 self.wtr.write_str("(?m:^)")?;  in visit_pre()
128                 self.wtr.write_str("(?m:$)")?;  in visit_pre()
131                 self.wtr.write_str(r"\A")?;  in visit_pre()
134                 self.wtr.write_str(r"\z")?;  in visit_pre()
137                 self.wtr.write_str(r"\b")?;  in visit_pre()
140                 self.wtr.write_str(r"\B")?;  in visit_pre()
143                 self.wtr.write_str(r"(?-u:\b)")?;  in visit_pre()
146                 self.wtr.write_str(r"(?-u:\B)")?;  in visit_pre()
150                     self.wtr.write_str("(")?;  in visit_pre()
156                     self.wtr.write_str("(?:")?;  in visit_pre()
176                         self.wtr.write_str("?")?;  in visit_post()
179                         self.wtr.write_str("*")?;  in visit_post()
182                         self.wtr.write_str("+")?;  in visit_post()
197                     self.wtr.write_str("?")?;  in visit_post()
201                 self.wtr.write_str(")")?;  in visit_post()
208         self.wtr.write_str("|")  in visit_alternation_in()
215             self.wtr.write_str("\\")?;  in write_literal_char()