Contents xix
3.7.2 Using Compiler Directives and Listing Source Lines .. 83
3.7.3 Terminating the Scanner ................. 85
3.7.4 Multicharacter Lookahead ................. 86
3.7.5 Performance Considerations ............... 87
3.7.6 Lexical Error Recovery .................. 89
3.8 Regular Expressions and Finite Automata ............ 92
3.8.1 Transforming a Regular Expression into an NFA .... 93
3.8.2 Creating the DFA ...................... 94
3.8.3 Optimizing Finite Automata ................ 97
3.8.4 Translating Finite Automata into Regular Expressions . 100
3.9 Summary .............................. 103
Exercises ................................. 106
4 Grammars and Parsing 113
4.1 Context-Free Grammars ...................... 114
4.1.1 Leftmost Derivations .................... 116
4.1.2 Rightmost Derivations ................... 116
4.1.3 Parse Trees ......................... 117
4.1.4 Other Types of Grammars ................. 118
4.2 Properties of CFGs ......................... 120
4.2.1 Reduced Grammars .................... 120
4.2.2 Ambiguity .......................... 121
4.2.3 Faulty Language Definition ................ 122
4.3 Transforming Extended Grammars ................ 122
4.4 Parsers and Recognizers ..................... 123
4.5 Grammar Analysis Algorithms .................. 127
4.5.1 Grammar Representation ................. 127
4.5.2 Deriving the Empty String ................. 128
4.5.3 First Sets .......................... 130
4.5.4 Follow Sets ......................... 134
Exercises ................................. 138
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