1 | /* Generated By:JavaCC: Do not edit this line. CharStream.java Version 4.0 */ |
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2 | package com.framsticks.framclipse.internal.parser; |
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3 | |
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4 | /** |
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5 | * This interface describes a character stream that maintains line and |
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6 | * column number positions of the characters. It also has the capability |
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7 | * to backup the stream to some extent. An implementation of this |
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8 | * interface is used in the TokenManager implementation generated by |
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9 | * JavaCCParser. |
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10 | * |
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11 | * All the methods except backup can be implemented in any fashion. backup |
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12 | * needs to be implemented correctly for the correct operation of the lexer. |
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13 | * Rest of the methods are all used to get information like line number, |
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14 | * column number and the String that constitutes a token and are not used |
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15 | * by the lexer. Hence their implementation won't affect the generated lexer's |
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16 | * operation. |
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17 | */ |
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18 | |
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19 | public interface CharStream { |
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20 | |
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21 | /** |
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22 | * Returns the next character from the selected input. The method |
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23 | * of selecting the input is the responsibility of the class |
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24 | * implementing this interface. Can throw any java.io.IOException. |
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25 | */ |
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26 | char readChar() throws java.io.IOException; |
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27 | |
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28 | /** |
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29 | * Returns the column position of the character last read. |
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30 | * @deprecated |
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31 | * @see #getEndColumn |
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32 | */ |
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33 | int getColumn(); |
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34 | |
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35 | /** |
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36 | * Returns the line number of the character last read. |
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37 | * @deprecated |
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38 | * @see #getEndLine |
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39 | */ |
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40 | int getLine(); |
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41 | |
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42 | /** |
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43 | * Returns the column number of the last character for current token (being |
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44 | * matched after the last call to BeginTOken). |
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45 | */ |
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46 | int getEndColumn(); |
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47 | |
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48 | /** |
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49 | * Returns the line number of the last character for current token (being |
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50 | * matched after the last call to BeginTOken). |
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51 | */ |
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52 | int getEndLine(); |
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53 | |
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54 | /** |
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55 | * Returns the column number of the first character for current token (being |
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56 | * matched after the last call to BeginTOken). |
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57 | */ |
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58 | int getBeginColumn(); |
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59 | |
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60 | /** |
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61 | * Returns the line number of the first character for current token (being |
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62 | * matched after the last call to BeginTOken). |
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63 | */ |
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64 | int getBeginLine(); |
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65 | |
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66 | /** |
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67 | * Backs up the input stream by amount steps. Lexer calls this method if it |
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68 | * had already read some characters, but could not use them to match a |
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69 | * (longer) token. So, they will be used again as the prefix of the next |
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70 | * token and it is the implemetation's responsibility to do this right. |
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71 | */ |
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72 | void backup(int amount); |
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73 | |
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74 | /** |
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75 | * Returns the next character that marks the beginning of the next token. |
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76 | * All characters must remain in the buffer between two successive calls |
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77 | * to this method to implement backup correctly. |
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78 | */ |
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79 | char BeginToken() throws java.io.IOException; |
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80 | |
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81 | /** |
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82 | * Returns a string made up of characters from the marked token beginning |
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83 | * to the current buffer position. Implementations have the choice of returning |
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84 | * anything that they want to. For example, for efficiency, one might decide |
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85 | * to just return null, which is a valid implementation. |
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86 | */ |
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87 | String GetImage(); |
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88 | |
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89 | /** |
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90 | * Returns an array of characters that make up the suffix of length 'len' for |
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91 | * the currently matched token. This is used to build up the matched string |
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92 | * for use in actions in the case of MORE. A simple and inefficient |
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93 | * implementation of this is as follows : |
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94 | * |
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95 | * { |
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96 | * String t = GetImage(); |
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97 | * return t.substring(t.length() - len, t.length()).toCharArray(); |
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98 | * } |
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99 | */ |
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100 | char[] GetSuffix(int len); |
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101 | |
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102 | /** |
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103 | * The lexer calls this function to indicate that it is done with the stream |
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104 | * and hence implementations can free any resources held by this class. |
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105 | * Again, the body of this function can be just empty and it will not |
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106 | * affect the lexer's operation. |
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107 | */ |
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108 | void Done(); |
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109 | |
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110 | } |
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