Download presentation

1
Lexical Analysis Arial Font Family

2
**Figure 3.1: Interactions between the lexical analyzer and the parser**

3
**Figure 3.2: Examples of tokens**

4
**Figure 3.3: Using a pair of input buffers**

5
**Figure 3.4: Sentinels at the end of each buffer**

6
**Figure 3.5: Lookahead code with sentinels**

7
**Figure 3.6: Definitions of operations on languages**

8
**Figure 3.7: Algebraic laws for regular expressions**

9
**Figure 3.8: Lex regular expressions**

10
**Figure 3.9: Filename expressions used by the shell command sh**

11
**Figure 3.10: A grammar for branching statements**

12
**Figure 3.11: Patterns for tokens of Example 3.8**

13
**Figure 3.12: Tokens, their patterns, and attribute values**

14
**Figure 3.13: Transition diagram for relop**

15
**Figure 3.14: A transition diagram for id's and keywords**

16
**Figure 3.15: Hypothetical transition diagram for the keyword then**

17
**Figure 3.16: A transition diagram for unsigned numbers**

18
**Figure 3.17: A transition diagram for whitespace**

19
**Figure 3.18: Sketch of implementation of relop transition diagram**

20
**Figure 3.19: Algorithm to compute the failure function for keyword blb2 . . . bn**

21
**Figure 3. 20: The KMP algorithm tests whether string ala2**

Figure 3.20: The KMP algorithm tests whether string ala2 . . a, contains a single keyword bl b bn as a substring in O(m + n) time

22
**Figure 3.21: Trie for keywords he, she, his, hers**

23
**Figure 3.22: Creating a lexical analyzer with Lex**

24
**Figure 3.23: Lex program for the tokens of Fig. 3.12**

25
**Figure 3.24: A nondeterministic finite automaton**

26
**Figure 3.25: Transition table for the NFA of Fig. 3.24**

27
**Figure 3.26: NFA accepting aa* 1 bb***

28
**Figure 3.27: Simulating a DFA**

29
**Figure 3.28: DFA accepting (aJb)*abb**

30
**Figure 3.29: NFA for Exercise 3.6.3**

31
**Figure 3.30: NFA for Exercise 3.6.4**

32
**Figure 3.31: Operations on NFA states**

33
**Figure 3.32: The subset construction**

34
**Figure 3.33: Computing E- closure(T)**

35
**Figure 3.34: NFA N for (alb)*abb**

36
**Figure 3.35: Transition table Dtran for DFA D**

37
**Figure 3.36: Result of applying the subset construction to Fig. 3.34**

38
**Figure 3.37: Simulating an NFA**

39
**Figure 3.38: Adding a new state s, which is known not to be on newstates**

40
**Figure 3.39: Implementation of step (4) of Fig. 3.37**

41
**Figure 3.40: NFA for the union of two regular expressions**

42
**Figure 3.41: NFA for the concatenation of two regular expressions**

43
**Figure 3.42: NFA for the closure of a regular expression**

44
**Figure 3.43: Parse tree for (alb)*abb**

45
Figure 3.44: NFA for r3

46
Figure 3.45: NFA for r5

47
Figure 3.46: NFA for r

48
**Figure 3.47: An NFA that has many fewer states than the smallest equivalent DFA**

49
Figure 3.48: Initial cost and per-string-cost of various methods of recognizing the language of a regular expression

50
Figure 3.49: A Lex program is turned into a transition table and actions, which are used by a finite-automaton simulator

51
**Figure 3.50: An NFA constructed from a Lex program**

52
**Figure 3.51: NFA's for a, abb, and a*b+**

53
Figure 3.52: Combined NFA

54
**Figure 3.53: Sequence of sets of states entered when processing input aaba**

55
**Figure 3.54: Transition graph for DFA handling the patterns a, abb, and a*b+**

56
**Figure 3.55: NFA recognizing the keyword IF**

57
**Figure 3.56: Syntax tree for (aJb)*abb#**

58
**Figure 3.57: NFA constructed by Algorithm 3.23 for (a(b)*abb#**

59
**Figure 3.58: Rules for computing nullable and firstpos**

60
**Figure 3.59: firstpos and lastpos for nodes in the syntax tree for (alb)*abb#**

61
**Figure 3.60: The function followpos**

62
**Figure 3.61: Directed graph for the function followpos**

63
**Figure 3.62: Construction of a DFA directly from a regular expression**

64
**Figure 3.63: DFA constructed from Fig. 3.57**

65
**Figure 3.64: Construction of Π new**

66
**Figure 3.65: Transition table of minimum-state DFA**

67
**Figure 3.66: Data structure for representing transition tables**

68
Terima Kasih

Similar presentations

OK

Bellwork Do the following problem on a ½ sheet of paper and turn in.

Bellwork Do the following problem on a ½ sheet of paper and turn in.

© 2018 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on major domains of the earth for class 6 Ppt on bill gates Ppt on bionics research Ppt on nokia company profile Ppt on games and sports Ppt on loops in c language Ppt on marketing management free download Download ppt on human eye class 10 Ppt on the road not taken interpretation Ppt on amplitude shift keying circuit