A bottom-up parse corresponds to the construction of a parse tree for an input string beginning at the leaves (the bottom) and working up towards the root (the top) . It is convenient to describe parsing as the process of building parse trees, althou

预测分析法（LL(1)方法）的基本思想是：从文法开始符S出发，从左到右扫描源程序，每次通过向前查看 1 个字符，选择合适的产生式，生成中间推导过程以及句子的最左推导。本程序可以输入预测分析表，输出最左推导和中间过程。(The basic idea of prediction analysis method (LL (1)) is to start from the grammar start symbol S, and scan the source program from left to r