ROOT (token: short_text [lag_newlines/spaces] {pos_id})
 °--expr: (1 +
 [0/0] {1}                             
     ¦--'(': ( [0/0] {2}                               
     ¦--expr: 1 +
2 [0/0] {3}                         
     ¦   ¦--expr: 1 [0/1] {6}                          
     ¦   ¦   °--NUM_CONST: 1 [0/0] {5}                 
     ¦   ¦--'+': + [0/0] {7}                           
     ¦   ¦--expr: 2 [1/1] {9}                          
     ¦   ¦   °--NUM_CONST: 2 [0/0] {8}                 
     ¦   ¦--'+': + [0/1] {10}                          
     ¦   °--expr: (
3 + [0/0] {11}                    
     ¦       ¦--'(': ( [0/0] {12}                      
     ¦       ¦--expr: 3 + 4 [1/2] {13}                 
     ¦       ¦   ¦--expr: 3 [0/1] {15}                 
     ¦       ¦   ¦   °--NUM_CONST: 3 [0/0] {14}        
     ¦       ¦   ¦--'+': + [0/1] {16}                  
     ¦       ¦   °--expr: 4 [0/0] {18}                 
     ¦       ¦       °--NUM_CONST: 4 [0/0] {17}        
     ¦       °--')': ) [1/0] {19}                      
     °--')': ) [1/0] {20}                              
