ROOT (token: short_text [lag_newlines/spaces] {pos_id})
 ¦--expr: a() [0/0] {1}                                
 ¦   ¦--expr: a [0/0] {3}                              
 ¦   ¦   °--SYMBOL_FUNCTION_CALL: a [0/0] {2}          
 ¦   ¦--'(': ( [0/0] {4}                               
 ¦   °--')': ) [0/0] {5}                               
 ¦--expr: b [1/1] {7}                                  
 ¦   °--SYMBOL: b [0/0] {6}                            
 °--COMMENT: # com [0/0] {8}                           
