情况语句

语法

casest = ithcasest / condcasest;
ithcasest = "ITHCASE" exp "OF" "BEGIN" statement $(';
statement) "END";
condcasest = "CASE" exp "OF" "BEGIN" condcs $('; condcs)
"OTHERWISE" statement "END";
condcs = conjunct ': statement;

情况语句的值是最后执行的那个分支的值。