ROOT (token: short_text [lag_newlines/spaces] {pos_id})
 °--expr: a <-  [0/0] {1}                              
     ¦--expr: a [0/1] {3}                              
     ¦   °--SYMBOL: a [0/0] {2}                        
     ¦--LEFT_ASSIGN: <- [0/1] {4}                      
     °--expr: funct [0/0] {5}                          
         ¦--FUNCTION: funct [0/0] {6}                  
         ¦--'(': ( [0/0] {7}                           
         ¦--')': ) [0/1] {8}                           
         °--expr: {
 bb [0/0] {9}                     
             ¦--'{': { [0/1] {10}                      
             ¦--expr: bbx [1/2] {12}                   
             ¦   °--SYMBOL: bbx [0/0] {11}             
             ¦--expr: x [1/2] {14}                     
             ¦   °--SYMBOL: x [0/0] {13}               
             °--'}': } [1/0] {15}                      
