recursive descent parser

<elist>-> <e><elist_tail>

<elist_tail>-> , <elist>



<etail>-> ^ <e>



<ntail>-> <n>


<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


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


procedure ELIST;E;if SUCCEEDED then ELIST_TAIL endifend ELIST;


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;


procedure E;N_value = 0;N;if SUCCEEDEDthen ETAIL endifend E;


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;


procedure N;D;if SUCCEEDEDthen N_value = N_value * 10 + D_value;NTAIL endifend N;


procedure NTAIL;if(NOT((next_inp_symbol = '^' | ',') OR EOL))then N endifend NTAIL;


procedure D;if next_inp_symbol is a digitthen compute D_value;GET_NEXT_SYMBOLelse SUCCEEDED = FALSE endifend D;

Evner: Ingeniørarbejde, Java, MySQL, PHP, Projekt Ledelse, Software Arkitektur, Software Testning

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Om arbejdsgiveren:
( 4 bedømmelser ) United States

Projekt ID: #3314007