ROOT (token: short_text [lag_newlines/spaces] {pos_id})
 ¦--expr: call( [0/0] {1}                              
 ¦   ¦--expr: call [0/0] {3}                           
 ¦   ¦   °--SYMBOL_FUNCTION_CALL: call [0/0] {2}       
 ¦   ¦--'(': ( [0/0] {4}                               
 ¦   ¦--expr: arg [0/1] {6}                            
 ¦   ¦   °--SYMBOL: arg [0/0] {5}                      
 ¦   ¦--',': , [0/0] {7}                               
 ¦   ¦--',': , [0/0] {8}                               
 ¦   ¦--expr: more_ [0/0] {10}                         
 ¦   ¦   °--SYMBOL: more_ [0/0] {9}                    
 ¦   °--')': ) [0/0] {11}                              
 °--expr: a[ ,  [1/0] {12}                             
     ¦--expr: a [0/0] {14}                             
     ¦   °--SYMBOL: a [0/0] {13}                       
     ¦--'[': [ [0/1] {15}                              
     ¦--',': , [0/1] {16}                              
     ¦--',': , [0/1] {17}                              
     ¦--SYMBOL_SUB: drop [0/1] {18}                    
     ¦--EQ_SUB: = [0/1] {19}                           
     ¦--expr: FALSE [0/0] {21}                         
     ¦   °--NUM_CONST: FALSE [0/0] {20}                
     °--']': ] [0/0] {22}                              
