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Lexical Analysis

Lexical Analysis. Arial Font Family. Figure 3.1: Interactions between the lexical analyzer and the parser. Figure 3.2: Examples of tokens. Figure 3.3: Using a pair of input buffers. Figure 3.4: Sentinels at the end of each buffer. Figure 3.5: Lookahead code with sentinels.

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Lexical Analysis

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  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 algorithmtests whether string ala2 . . a, contains asingle keyword bl b2 . . . bnas 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 recognizingthe language of a regular expression

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

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