Main Purpose Study an algorithm: – Translating a regular expression into a DFA via NFA

Special Notations for Repetitive Constructs Repetition – A → A  |  (left recursive), and – A →  A |  (right recursive) where  and  are arbitrary strings of terminals and non-terminals, and – In the first rule  does not begin with A and

Symbol table: major inherited attribute and major data structure in a compiler Principal operations: – Insert: store the information provided by name declarations when processing these declarations – Lookup: retrieve the information associated to a name when that name is used in the associated code

A stack-based environment will result in a dangling reference when the procedure is exited if a local variable in a procedure can be returned to the caller The simplest example:

Why Compiler Writing machine language-numeric codes is time consuming and tedious

The idea of Recursive-Descent Parsing Viewing the grammar rule for a non-terminal A as a definition for a procedure to recognize an A The right-hand side of the grammar for A specifies the structure of the code for this procedure The Expression Grammar:

A bottom-up parser uses an explicit stack to perform a parse – The parsing stack contains tokens, nonterminals as well as some extra state information – The stack is empty at the beginning of a bottom-up parse, and will contain the start symbol at the end of a successful parse

8.1.1 Three-Address Code 8.1.2 Data Structures for theImplementation of Three-Address Code

一、指针数组的定义、引用，main 函数形参的意义 二、应用指针数组处理多个字符串，编写带有形参的主函数 三、指针数组的应用

讨论启发式，老师提出问题，引导学生讨论，启发思路，必要时写出关键语句要求 学生补全，或由学生上教师机演示，注意检查发现同学中的多种解法