pl0 文法 编译器

（1）扩充一维整型数组。
扩充var数组：VAR <数组标识名>（<下界>：<上界>）〈下界〉和〈上界〉可用常量标识名。
（2）扩充条件语句的功能使其为：IF<条件>THEN<语句>[ELSE<语句>]
（3）增加repeat重复语句:
REPEAT<语句>{ <语句>}UNTIL<条件>
,pl0 compiler grammar (1) the expansion of one-dimensional array of integers. Var array expansion: VAR < array identification name>　(< lower bound> : < upper bound> ) < lower bound " and"　upper bound>　of available constants logo. (2) the expansion of the function of conditional statements as to: IF < condition>　THEN < statement>　[ELSE < statement> ] (3) an increase in repeat repeat statement: REPEAT < statements>　(　< statements> ) UNTIL < condition>