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1 package plparser;
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2
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3 import java.io.FileReader;
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4 import java.io.InputStream;
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5 import java.io.InputStreamReader;
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6 import java.util.Iterator;
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7
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8 public abstract class PLScannerImpl<Node> implements PLScanner<Node> {
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9
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10 public int lineno;
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11 public Token<Node> nextToken;
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12 public Dictionary<Node> dict;
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13 public PLScanner<Node> next;
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14 public InputStreamReader file;
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15 public String filename;
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16 public PLScanner<Node> prev;
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17 public Token<Node> nullToken;
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18 public String prompt;
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19 public static final int BufferSize = 4096;
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20
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11
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21 /**
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22 * Construtor for push Scanner
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23 * @param p previous scanner
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24 * @param dict dictionary
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25 * @param nullToken shared null token
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26 */
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27 public PLScannerImpl(PLScanner<Node> p,
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28 Dictionary<Node> dict, Token<Node> nullToken) {
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29 this.prev = p;
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30 this.dict = dict;
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31 this.nullToken = nullToken;
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32 }
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33
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11
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34
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35 public PLScannerImpl() {
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36 this.dict = new Dictionary<Node>();
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37 this.nullToken = new Token<Node>("",TokenID.NULL);
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38 this.prev = null;
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39 }
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40
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41
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42 public PLScanner<Node> popScanner() {
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43 return prev;
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44 }
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45
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46 private PLScanner<Node> findFileName() {
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47 for(PLScanner<Node> s = this;s!=null ; s = s.prev()) {
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48 if (s.filename()!=null) return s;
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49 }
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50 return null;
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51 }
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52 /*
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53 * Read From String
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54 */
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55
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56 public void error(String err) {
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57 PLScanner<Node> s = findFileName();
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58 if (s!=null) {
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59 System.err.print(s.filename()+":"+s.lineno()+": ");
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60 }
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61 System.err.println("error: "+err);
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62 }
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63
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64 public Iterable<Token<Node>> scanToken(String exp) {
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65 set(exp);
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66 return iterator();
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67 }
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68
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69 public Iterable<Token<Node>> scanToken(FileReader file) {
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70 set(file);
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71 return iterator();
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72 }
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73
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74 private Iterable<Token<Node>> iterator() {
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75 return new Iterable<Token<Node>>() {
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76 public Iterator<Token<Node>> iterator() {
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77 return new Iterator<Token<Node>>() {
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78 public boolean hasNext() {
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79 return hasRemaining();
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80 }
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81 public Token<Node> next() {
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82 return nextToken();
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83 }
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84 public void remove() {
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85 }
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86 };
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87 }
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88 };
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89 }
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90
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91 public PLScanner<Node> setFile(InputStream newfile, String prompt) {
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92 this.filename = newfile.toString();
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93 nextToken = nullToken;
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94 this.prompt = prompt;
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95 set(new InputStreamReader(newfile));
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96 return this;
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97 }
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98
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99 @Override
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100 public String filename() {
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101 return filename;
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102 }
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103
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104 @Override
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105 public int lineno() {
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106 return lineno;
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107 }
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108
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109 @Override
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110 public PLScanner<Node> prev() {
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111 return prev;
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112 }
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113
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114 public Dictionary<Node> dictionary() {
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115 return dict;
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116 }
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117
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118 } |
