grammar.txt

program -> var_section body inputs *
var_section -> id_list SEMICOLON *
id_list -> ID COMMA id_list | ID *
body -> LBRACE stmt_list RBRACE *
stmt_list -> stmt stmt_list | stmt *
stmt -> assign_stmt | while_stmt | if_stmt | switch_stmt | for_stmt | output_stmt | input_stmt *
assign_stmt -> ID EQUAL primary SEMICOLON | ID EQUAL expr SEMICOLON *
expr -> primary op primary *
primary -> ID | NUM *
op -> PLUS | MINUS | MULT | DIV *
output_stmt -> output ID SEMICOLON *
input_stmt -> input ID SEMICOLON *
while_stmt -> WHILE condition body *
if_stmt -> IF condition body *
condition -> primary relop primary *
relop -> GREATER | LESS | NOTEQUAL *
switch_stmt -> SWITCH ID LBRACE case_list RBRACE | SWITCH ID LBRACE case_list default_case RBRACE *
for_stmt -> FOR LPAREN assign_stmt condition SEMICOLON assign_stmt RPAREN body *
case_list -> case case_list | case *
case -> CASE NUM COLON body *
default_case -> DEFAULT COLON body *
inputs -> num_list *
num_list -> NUM | NUM num_list *