recursive descent parser

<elist>-> <e><elist_tail> <elist_tail>-> , <elist> <elist_tail>-> <e>-><n><etail> <etail>-> ^ <e> <etail>-> <n>-><d><ntail> <ntail>-> <n> <ntail>-> <d>-> 0 |1 | 2| 3| 4| 5| 6| 7| 8| 9 by using above grammer implement recursive descent parser the grammer generates statements of form 2^2^3,15,20^2 for which parser outputs 256 15 400 this is example which explains basic idea of rdp note:? 1) keep all variables declared globally as they are except ? N_value 2) declare N_value locally to procedure E 3) make N_value a pass by value parameter to procedure ETAIL 4) make N_value pass by reference parameter to both procedure N and NTAIL ## Deliverables procedure RDPARSER; while NOT EOF do SUCCEEDED = TRUE; GET_INP_LINE; //reads in the next input line GET_NEXT_SYMBOL; //returns the next input symbol ELIST; if SUCCEEDEDthen SUCCESS_MESSAGE;else FAILURE_MESSAGE enifendwhileend RDPARSER Code: procedure ELIST;E;if SUCCEEDED then ELIST_TAIL endifend ELIST; Code: procedure ELIST_TAIL;if EOLthen print E_Valueelse if next_inp_symbol = ","then print E_Value;GET_NEXT_SYMBOL;ELIST;else SUCCEEDED = FALSE endifendifend ELIST_TAIL; Code: procedure E;N_value = 0;N;if SUCCEEDEDthen ETAIL endifend E; Code: procedure ETAILif(NOT((next_inp_symbol = ",") OR EOL))then if next_inp_symbol = '^'then GET_NEXT_SYMBOL;E;E_value = N_value ** E_value;else SUCCEEDED = FALSE endifelse E_value = N_value enidfend ETAIL; Code: procedure N;D;if SUCCEEDEDthen N_value = N_value * 10 + D_value;NTAIL endifend N; Code: procedure NTAIL;if(NOT((next_inp_symbol = '^' | ',') OR EOL))then N endifend NTAIL; Code: procedure D;if next_inp_symbol is a digitthen compute D_value;GET_NEXT_SYMBOLelse SUCCEEDED = FALSE endifend D;