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考題提供第3 ,4, 5 章 共20 題 題目類型(簡答 是非 選擇 計算都有) 1 請說明使用Syntax Directed Translations 可能產生什麼問題 答 1 Grammar specification may be tedious (e.g., to achieve LALR(1)) 2 May need to rewrite the grammar to incorporate different semantics 3 Modularity is impossible to achieve 4 Some programming languages allow forward declarations (Algol, ML and Java) 2 何謂 Dynamic Scope 和 Static Scope,簡單敘述之 答 略 3 Type checking 的功能是什麼,簡單敘述之 答 ensure that operations are used with the correct types (Enforces intended interpretation of values because nothing else will!) 4 何謂 Statically typed 和Dynamically typed,簡單敘述之 並分別說出C, Java, Cool, ML, Scheme 各屬於何種 答 Statically typed: (Almost) all checking of types is done as part of compilation EX C, Java, Cool, ML Dynamically typed: Almost all checking of types is done as part of program execution EX Scheme 5 何謂Attribute Grammars,簡單敘述之 答 Generalize syntax directed translations Every grammar symbol can have several attributes Every production is associated with evaluation rules Context rules The order of evaluation is automatically determined declarative Multiple visits of the abstract syntax tree 1/9 6說明 Compiler編譯的五個過程且分別簡單 明它們 1. Lexical Analyzer (Scanner) Takes source Program and Converts into tokens 2. Syntax Analyzer (Parser) Takes tokens and constructs a parse tree. 3. Semantic Analyzer Takes a parse tree and constructs an abstract syntax tree with attributes. 4 Syntax Directed Translation Takes an abstract syntax tree and produces an Interpreter code (Translation output) 5. Intermediate-code Generator Takes an abstract syntax tree and produces un- optimized Intermediate code 7是非題 A 正確Syntax directed translation attaches actions to the grammar rules (productions).The actions are executed during the compilation B 正確 A