1 | // HRParser v1.0.1 (25.Sep.2000)
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2 | // Simple and fast parser classes.
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3 | // by Colin A Ridgewell
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4 | //
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5 | // Copyright (C) 1999,2000 Hayden-R Ltd
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6 | // http://www.haydenr.com
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7 | //
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8 | // This program is free software; you can redistribute it and/or modify it
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9 | // under the terms of the GNU General Public License as published by the
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10 | // Free Software Foundation; either version 2 of the License, or (at your
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11 | // option) any later version.
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12 | //
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13 | // This program is distributed in the hope that it will be useful, but
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14 | // WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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15 | // or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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16 | // more details.
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17 | //
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18 | // You should have received a copy of the GNU General Public License along
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19 | // with this program (gnu_license.htm); if not, write to the
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20 | //
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21 | // Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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22 | //
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23 | // To contact us via e-mail use the following addresses...
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24 | //
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25 | // bug@haydenr.u-net.com - to report a bug
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26 | // support@haydenr.u-net.com - for general support
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27 | // wishlist@haydenr.u-net.com - add new requirement to wish list
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28 | //
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29 | unit HRParser;
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30 |
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31 | interface
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32 |
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33 | uses
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34 | Classes, SysUtils, HRBuffers;
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35 |
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36 | type
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37 | THRTokenType = Byte;
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38 |
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39 | const
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40 | HR_PARSER_STREAM_BUFFER_SIZE = 2048; {bytes}
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41 | HR_PARSER_TOKEN_BUFFER_SIZE = 1024; {bytes}
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42 |
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43 | {THRParser tokens}
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44 | HR_TOKEN_NIL = 0;
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45 | HR_TOKEN_EOF = 1;
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46 | HR_TOKEN_CHAR = 2;
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47 |
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48 | {THRParserText tokens}
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49 | HR_TOKEN_TEXT_SPACE = 3;
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50 | HR_TOKEN_TEXT_SYMBOL = 4;
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51 | HR_TOKEN_TEXT_INTEGER = 5;
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52 | HR_TOKEN_TEXT_FLOAT = 6;
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53 |
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54 | type
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55 | THRToken = record
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56 | Token: PChar;
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57 | TokenType: THRTokenType;
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58 | SourcePos: Longint;
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59 | Line: Longint;
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60 | LinePos: Integer;
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61 | end;
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62 |
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63 | THRParser = class( TObject )
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64 | private
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65 | function GetSource: TStream;
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66 | procedure SetSource(Value: TStream);
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67 | procedure SetSourcePos(Value: LongInt);
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68 | protected
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69 | FSourceBuf: THRBufferStream;
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70 | FSourcePos: LongInt;
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71 | FLine: Longint;
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72 | FLineStartSourcePos: Longint;
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73 | FTokenBuf: THRBufferChar;
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74 | FToken: THRToken;
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75 | procedure IncLine;
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76 | procedure SkipToSourcePos(const Pos: Longint);
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77 | procedure SkipBlanks;
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78 | procedure GetNextToken; virtual;
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79 | public
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80 | constructor Create; virtual;
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81 | destructor Destroy; override;
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82 | property Source: TStream read GetSource write SetSource;
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83 | property SourcePos: Longint read FSourcePos write SetSourcePos;
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84 | property Token: THRToken read FToken;
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85 | function NextToken: THRToken;
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86 | end;
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87 |
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88 | THRParserText = class( THRParser )
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89 | private
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90 | protected
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91 | procedure GetNextToken; override;
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92 | public
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93 | constructor Create; override;
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94 | destructor Destroy; override;
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95 | end;
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96 |
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97 | implementation
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98 |
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99 |
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100 | { T H R P a r s e r }
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101 |
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102 | constructor THRParser.Create;
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103 | begin
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104 | FSourceBuf := THRBufferStream.Create;
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105 | FSourceBuf.Size := HR_PARSER_STREAM_BUFFER_SIZE;
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106 | FTokenBuf := THRBufferChar.Create;
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107 | FTokenBuf.Size := HR_PARSER_TOKEN_BUFFER_SIZE;
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108 | FSourcePos := 0;
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109 | end;
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110 |
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111 |
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112 | destructor THRParser.Destroy;
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113 | begin
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114 | FTokenBuf.Free;
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115 | FTokenBuf := nil;
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116 | FSourceBuf.Free;
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117 | FSourceBuf := nil;
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118 | inherited Destroy;
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119 | end;
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120 |
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121 |
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122 | function THRParser.GetSource: TStream;
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123 | begin
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124 | Result := FSourceBuf.Stream;
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125 | end;
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126 |
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127 |
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128 | procedure THRParser.SetSource(Value: TStream);
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129 | begin
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130 | FSourceBuf.Stream := Value;
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131 | end;
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132 |
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133 |
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134 | procedure THRParser.SetSourcePos(Value: LongInt);
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135 | begin
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136 | SkipToSourcePos( Value );
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137 | end;
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138 |
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139 |
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140 | procedure THRParser.IncLine;
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141 | begin
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142 | Inc( FLine );
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143 | FLineStartSourcePos := FSourcePos;
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144 | end;
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145 |
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146 |
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147 | procedure THRParser.SkipToSourcePos(const Pos: Longint);
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148 | begin
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149 | FSourcePos := 0;
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150 | FLine := 0;
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151 | FLineStartSourcePos := 0;
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152 | FSourceBuf[ FSourcePos ];
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153 | while not FSourceBuf.EOB and ( FSourcePos < Pos ) do
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154 | begin
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155 | if FSourceBuf[ FSourcePos ] = #10 then IncLine;
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156 | Inc( FSourcePos );
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157 | FSourceBuf[ FSourcePos ];
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158 | end;
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159 | end;
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160 |
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161 |
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162 | procedure THRParser.SkipBlanks;
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163 | begin
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164 | FSourceBuf[ FSourcePos ];
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165 | while not FSourceBuf.EOB do
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166 | begin
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167 | case FSourceBuf[ FSourcePos ] of
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168 | #32..#255 : Exit;
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169 | #10 : IncLine;
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170 | end;
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171 | Inc( FSourcePos );
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172 | FSourceBuf[ FSourcePos ];
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173 | end;
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174 | end;
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175 |
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176 |
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177 | procedure THRParser.GetNextToken;
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178 | begin
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179 | FSourceBuf[ FSourcePos ];
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180 | if not FSourceBuf.EOB then
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181 | begin
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182 | {single char}
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183 | FTokenBuf.Write( FSourceBuf[ FSourcePos ] );
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184 | Inc( FSourcePos );
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185 | FToken.TokenType := HR_TOKEN_CHAR;
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186 | end
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187 | else
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188 | begin
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189 | {end of buffer}
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190 | FToken.TokenType := HR_TOKEN_EOF;
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191 | end;
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192 | end;
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193 |
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194 |
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195 |
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196 | function THRParser.NextToken: THRToken;
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197 | begin
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198 | FTokenBuf.Position := 0;
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199 |
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200 | SkipBlanks;
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201 |
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202 | {store start pos of token}
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203 | with FToken do
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204 | begin
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205 | SourcePos := FSourcePos;
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206 | Line := FLine;
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207 | LinePos := FSourcePos - FLineStartSourcePos;
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208 | end;
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209 |
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210 | GetNextToken;
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211 |
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212 | FTokenBuf.Write( #0 ); {null terminate.}
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213 | FToken.Token := FTokenBuf.Buffer;
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214 | Result := FToken;
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215 | end;
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216 |
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217 |
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218 | { T H R P a r s e r T e x t }
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219 |
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220 | constructor THRParserText.Create;
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221 | begin
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222 | inherited Create;
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223 | end;
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224 |
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225 |
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226 | destructor THRParserText.Destroy;
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227 | begin
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228 | inherited Destroy;
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229 | end;
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230 |
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231 |
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232 | procedure THRParserText.GetNextToken;
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233 | begin
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234 | repeat
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235 |
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236 | {spaces}
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237 | if FSourceBuf[ FSourcePos ] = ' ' then
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238 | begin
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239 | FTokenBuf.Write( FSourceBuf[ FSourcePos ] );
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240 | Inc( FSourcePos );
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241 | while FSourceBuf[ FSourcePos ] = ' ' do
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242 | begin
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243 | FTokenBuf.Write( FSourceBuf[ FSourcePos ] );
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244 | Inc( FSourcePos );
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245 | end;
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246 | FToken.TokenType := HR_TOKEN_TEXT_SPACE;
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247 | Break;{out of repeat}
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248 | end;
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249 |
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250 | {symbols}
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251 | if FSourceBuf[ FSourcePos ] in [ 'A'..'Z', 'a'..'z', '_' ] then
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252 | begin
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253 | FTokenBuf.Write( FSourceBuf[ FSourcePos ] );
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254 | Inc( FSourcePos );
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255 | while True do
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256 | begin
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257 | case FSourceBuf[ FSourcePos ] of
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258 |
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259 | 'A'..'Z', 'a'..'z', '0'..'9', '_' :
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260 | begin
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261 | FTokenBuf.Write( FSourceBuf[ FSourcePos ] );
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262 | Inc( FSourcePos );
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263 | end;
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264 |
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265 | '''' :
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266 | begin{apostrophies}
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267 | if FSourceBuf[ FSourcePos + 1 ] in [ 'A'..'Z', 'a'..'z', '0'..'9', '_' ] then
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268 | begin
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269 | FTokenBuf.Write( FSourceBuf[ FSourcePos ] );
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270 | Inc( FSourcePos );
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271 | end
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272 | else
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273 | Break;
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274 | end;
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275 |
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276 | '-' :
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277 | begin{hyphenated words}
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278 | if FSourceBuf[ FSourcePos + 1 ] in [ 'A'..'Z', 'a'..'z', '0'..'9', '_' ] then
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279 | begin
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280 | FTokenBuf.Write( FSourceBuf[ FSourcePos ] );
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281 | Inc( FSourcePos );
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282 | end
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283 | else
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284 | Break;
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285 | end;
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286 |
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287 | else
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288 | Break;
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289 | end;{case}
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290 | end;
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291 | FToken.TokenType := HR_TOKEN_TEXT_SYMBOL;
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292 | Break;{out of repeat}
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293 | end;
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294 |
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295 | {numbers}
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296 | if ( FSourceBuf[ FSourcePos ] in [ '0'..'9' ] ) or
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297 | ( ( FSourceBuf[ FSourcePos ] = '-' ) and ( FSourceBuf[ FSourcePos + 1 ] in [ '.', '0'..'9' ] ) ) then
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298 | begin
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299 |
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300 | {integer numbers}
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301 | FTokenBuf.Write( FSourceBuf[ FSourcePos ] );
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302 | Inc( FSourcePos );
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303 | while FSourceBuf[ FSourcePos ] in [ '0'..'9' ] do
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304 | begin
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305 | FTokenBuf.Write( FSourceBuf[ FSourcePos ] );
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306 | Inc( FSourcePos );
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307 | FToken.TokenType := HR_TOKEN_TEXT_INTEGER;
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308 | end;
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309 |
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310 | {floating point numbers}
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311 | while ( FSourceBuf[ FSourcePos ] in [ '0'..'9', 'e', 'E', '+', '-' ] ) or
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312 | ( ( FSourceBuf[ FSourcePos ] = '.') and ( FSourceBuf[ FSourcePos + 1 ] <> '.' ) ) do
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313 | begin
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314 | FTokenBuf.Write( FSourceBuf[ FSourcePos ] );
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315 | Inc( FSourcePos );
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316 | FToken.TokenType := HR_TOKEN_TEXT_FLOAT;
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317 | end;
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318 |
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319 | Break;{out of repeat}
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320 | end;
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321 |
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322 | inherited GetNextToken;
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323 | {Break;}{out of repeat}
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324 |
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325 | until( True );
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326 | end;
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327 |
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328 |
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329 | end.
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330 |
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