ROOT (token: short_text [lag_newlines/spaces] {pos_id}) 
 ¦--expr: foo(
 [0/0] {1}                              
 ¦   ¦--expr: foo [0/0] {3}                             
 ¦   ¦   °--SYMBOL_FUNCTION_CALL: foo [0/0] {2}         
 ¦   ¦--'(': ( [0/2] {4}                                
 ¦   ¦--SYMBOL_SUB: data [1/1] {5}                      
 ¦   ¦--EQ_SUB: = [0/1] {6}                             
 ¦   ¦--expr: mtcar [0/0] {8}                           
 ¦   ¦   °--SYMBOL: mtcar [0/0] {7}                     
 ¦   ¦--',': , [0/2] {9}                                
 ¦   ¦--SYMBOL_SUB: x [1/1] {10}                        
 ¦   ¦--EQ_SUB: = [0/1] {11}                            
 ¦   ¦--expr: cyl [0/0] {13}                            
 ¦   ¦   °--SYMBOL: cyl [0/0] {12}                      
 ¦   ¦--',': , [0/2] {14}                               
 ¦   ¦--SYMBOL_SUB: y [1/1] {15}                        
 ¦   ¦--EQ_SUB: = [0/1] {16}                            
 ¦   ¦--expr: wt [0/1] {18}                             
 ¦   ¦   °--SYMBOL: wt [0/0] {17}                       
 ¦   ¦--COMMENT: #<< [0/0] {19}                         
 ¦   °--')': ) [1/0] {20}                               
 ¦--expr: libra [3/0] {21}                              
 ¦   ¦--expr: libra [0/0] {23}                          
 ¦   ¦   °--SYMBOL_FUNCTION_CALL: libra [0/0] {22}      
 ¦   ¦--'(': ( [0/0] {24}                               
 ¦   ¦--expr: ggplo [0/0] {26}                          
 ¦   ¦   °--SYMBOL: ggplo [0/0] {25}                    
 ¦   °--')': ) [0/0] {27}                               
 ¦--expr: ggplo [2/1] {28}                              
 ¦   ¦--expr: ggplo [0/1] {30}                          
 ¦   ¦   ¦--expr: ggplo [0/0] {32}                      
 ¦   ¦   ¦   °--SYMBOL_FUNCTION_CALL: ggplo [0/0] {31}  
 ¦   ¦   ¦--'(': ( [0/0] {33}                           
 ¦   ¦   ¦--expr: aes(x [0/0] {34}                      
 ¦   ¦   ¦   ¦--expr: aes [0/0] {36}                    
 ¦   ¦   ¦   ¦   °--SYMBOL_FUNCTION_CALL: aes [0/0] {35}
 ¦   ¦   ¦   ¦--'(': ( [0/0] {37}                       
 ¦   ¦   ¦   ¦--expr: x [0/0] {39}                      
 ¦   ¦   ¦   ¦   °--SYMBOL: x [0/0] {38}                
 ¦   ¦   ¦   ¦--',': , [0/1] {40}                       
 ¦   ¦   ¦   ¦--expr: y [0/0] {42}                      
 ¦   ¦   ¦   ¦   °--SYMBOL: y [0/0] {41}                
 ¦   ¦   ¦   °--')': ) [0/0] {43}                       
 ¦   ¦   ¦--',': , [0/1] {44}                           
 ¦   ¦   ¦--expr: data [0/0] {46}                       
 ¦   ¦   ¦   °--SYMBOL: data [0/0] {45}                 
 ¦   ¦   °--')': ) [0/0] {47}                           
 ¦   ¦--'+': + [0/2] {48}                               
 ¦   ¦--expr: geom_ [1/1] {49}                          
 ¦   ¦   ¦--expr: geom_ [0/0] {51}                      
 ¦   ¦   ¦   °--SYMBOL_FUNCTION_CALL: geom_ [0/0] {50}  
 ¦   ¦   ¦--'(': ( [0/0] {52}                           
 ¦   ¦   °--')': ) [0/0] {53}                           
 ¦   ¦--'+': + [0/1] {54}                               
 ¦   ¦--COMMENT: #<< [0/2] {55}                         
 ¦   °--expr: scale [1/0] {56}                          
 ¦       ¦--expr: scale [0/0] {58}                      
 ¦       ¦   °--SYMBOL_FUNCTION_CALL: scale [0/0] {57}  
 ¦       ¦--'(': ( [0/0] {59}                           
 ¦       °--')': ) [0/0] {60}                           
 °--COMMENT: #<< [0/0] {61}                             
