Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like sql_compiler often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use sql_compiler, and based on these observations, apply Extract Interface, too.
1 | <?php |
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3 | abstract class sql_compiler { |
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4 | protected $skipDefaultOrderBy; |
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5 | protected $store; |
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6 | public $error; |
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7 | protected $join_target_properties; |
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8 | protected $offset; |
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9 | protected $limit; |
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10 | protected $cache; |
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11 | protected $path; |
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12 | protected $_SCAN_WS = array(" " => true, "\t" => true, "\n" => true ,"\r" => true); |
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13 | protected $_SCAN_AZ = array("a" => true, "A" => true, "b" => true, "B" => true, "c" => true, "C" => true, "d" => true, "D" => true, "e" => true, "E" => true, "f" => true, "F" => true, "g" => true, "G" => true, "h" => true, "H" => true, "i" => true, "I" => true, "j" => true, "J" => true, "k" => true, "K" => true, "l" => true, "L" => true, "m" => true, "M" => true, "n" => true, "N" => true, "o" => true, "O" => true, "p" => true, "P" => true, "q" => true, "Q" => true, "r" => true, "R" => true, "s" => true, "S" => true, "t" => true, "T" => true, "u" => true, "U" => true, "v" => true, "V" => true, "w" => true, "W" => true, "x" => true, "X" => true, "y" => true, "Y" => true, "z" => true, "Z" => true); |
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14 | protected $_SCAN_AZ_09 = array("a" => true, "A" => true, "b" => true, "B" => true, "c" => true, "C" => true, "d" => true, "D" => true, "e" => true, "E" => true, "f" => true, "F" => true, "g" => true, "G" => true, "h" => true, "H" => true, "i" => true, "I" => true, "j" => true, "J" => true, "k" => true, "K" => true, "l" => true, "L" => true, "m" => true, "M" => true, "n" => true, "N" => true, "o" => true, "O" => true, "p" => true, "P" => true, "q" => true, "Q" => true, "r" => true, "R" => true, "s" => true, "S" => true, "t" => true, "T" => true, "u" => true, "U" => true, "v" => true, "V" => true, "w" => true, "W" => true, "x" => true, "X" => true, "y" => true, "Y" => true, "z" => true, "Z" => true, "_" => true, "0" => true, "1" => true, "2" => true, "3" => true, "4" => true, "5" => true, "6" => true, "7" => true, "8" => true, "9" => true); |
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15 | protected $_SCAN_NUM = array("0" => true, "1" => true, "2" => true, "3" => true, "4" => true, "5" => true, "6" => true, "7" => true, "8" => true, "9" => true); |
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16 | protected $_SCAN_NUM_START = array("0" => true, "1" => true, "2" => true, "3" => true, "4" => true, "5" => true, "6" => true, "7" => true, "8" => true, "9" => true, "-" => true); |
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17 | protected $_SCAN_CMP = array("~" => array("=" => array("FIN" => true)), "=" => array("=" => array("FIN" => true), "FIN" => true, "~" => array("FIN" => true, "~" => array("FIN" => true)), "*" => array("FIN" => true, "*" => array("FIN" => true)), "/" => array("FIN" => true)), "!" => array("=" => array("FIN" => true), "~" => array("FIN" => true, "~" => array("FIN" => true)), "*" => array("FIN" => true, "*" => array("FIN" => true)), "/" => array("FIN" => true, "/" => array("FIN" => true))), "<" => array("=" => array("FIN" => true), "FIN" => true), ">" => array("=" => array("FIN" => true), "FIN" => true), "/" => array("=" => array("=" => array("FIN" => true)))); |
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18 | |||
19 | |||
20 | protected function parse_const(&$YYBUFFER) { |
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21 | $YYCURSOR = 0; |
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22 | while (isset($this->_SCAN_WS[$YYBUFFER[$YYCURSOR]])) { |
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23 | $YYCURSOR++; |
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24 | } |
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25 | $value = ''; |
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26 | $yych = $YYBUFFER[$YYCURSOR]; |
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27 | switch (true) { |
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28 | case '"' === $yych: |
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29 | case "'" === $yych: |
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30 | $quote = $yych; |
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31 | $yych = $YYBUFFER[++$YYCURSOR]; |
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32 | while ($yych !== "\0" && $yych !== $quote) { |
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33 | if ($yych === "\\") { |
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34 | $yych = $YYBUFFER[++$YYCURSOR]; |
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35 | if ($yych !== $quote && $yych != "\\") { |
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36 | $value .= "\\"; |
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37 | } |
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38 | } |
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39 | $value .= $yych; |
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40 | $yych = $YYBUFFER[++$YYCURSOR]; |
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41 | } |
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42 | $YYBUFFER = substr($YYBUFFER, $YYCURSOR + 1); |
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43 | $node["id"] = "string"; |
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44 | $node["type"] = ($quote === '"') ? "double" : "single"; |
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45 | $node["value"] = stripslashes($value); |
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46 | return $node; |
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47 | break; |
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48 | case $this->_SCAN_NUM_START[$yych]: |
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49 | $value = $yych; |
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50 | $yych = $YYBUFFER[++$YYCURSOR]; |
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51 | while (isset($this->_SCAN_NUM[$yych])) { |
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52 | $value .= $yych; |
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53 | $yych = $YYBUFFER[++$YYCURSOR]; |
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54 | } |
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55 | if ($yych === '.') { |
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56 | $value .= $yych; |
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57 | $yych = $YYBUFFER[++$YYCURSOR]; |
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58 | while (isset($this->_SCAN_NUM[$yych])) { |
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59 | $value .= $yych; |
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60 | $yych = $YYBUFFER[++$YYCURSOR]; |
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61 | } |
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62 | $node["id"]="float"; |
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63 | $node["value"]=(float)$value; |
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64 | } else { |
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65 | $node["id"]="int"; |
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66 | $node["value"]=(int)$value;; |
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67 | } |
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68 | $YYBUFFER = substr($YYBUFFER, $YYCURSOR); |
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69 | return $node; |
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70 | break; |
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71 | } |
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72 | } |
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73 | |||
74 | protected function parse_ident(&$YYBUFFER) { |
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75 | /* parse identifier regs 1,2 and 3 |
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76 | |||
77 | reg[1]: tablename |
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78 | reg[2]: property name |
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79 | reg[3]: only used with 'my' properties |
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80 | */ |
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81 | $reg_id='^[[:space:]]*(([a-z_][a-z0-9_]*)(:[a-z]+)?([.][a-z_][a-z0-9_]*)?([.][a-z_][a-z0-9_]*)?)'; |
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82 | $reg_id.='[[:space:]]*'; |
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83 | |||
84 | $YYCURSOR = 0; |
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85 | while (isset($this->_SCAN_WS[$YYBUFFER[$YYCURSOR]])) { |
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86 | $YYCURSOR++; |
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87 | } |
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88 | $value = ''; |
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89 | $yych = $YYBUFFER[$YYCURSOR]; |
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90 | |||
91 | if ($this->_SCAN_AZ[$yych]) { |
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92 | $value .= $yych; |
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93 | $yych = $YYBUFFER[++$YYCURSOR]; |
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94 | while (isset($this->_SCAN_AZ_09[$yych])) { |
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95 | $value .= $yych; |
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96 | $yych = $YYBUFFER[++$YYCURSOR]; |
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97 | } |
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98 | $match_1 = $value; $value = ''; |
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99 | if ($yych === ':') { |
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100 | $yych = $YYBUFFER[++$YYCURSOR]; |
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101 | while (isset($this->_SCAN_AZ[$yych])) { |
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102 | $value .= $yych; |
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103 | $yych = $YYBUFFER[++$YYCURSOR]; |
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104 | } |
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105 | $record_id = $value; $value = ''; |
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106 | } |
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107 | View Code Duplication | if ($yych === '.') { |
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108 | $yych = $YYBUFFER[++$YYCURSOR]; |
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109 | if ($this->_SCAN_AZ[$yych]) { |
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110 | $value .= $yych; |
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111 | $yych = $YYBUFFER[++$YYCURSOR]; |
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112 | while (isset($this->_SCAN_AZ_09[$yych])) { |
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113 | $value .= $yych; |
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114 | $yych = $YYBUFFER[++$YYCURSOR]; |
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115 | } |
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116 | } |
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117 | $match_2 = $value; $value = ''; |
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118 | } |
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119 | View Code Duplication | if ($yych === '.') { |
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120 | $yych = $YYBUFFER[++$YYCURSOR]; |
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121 | if ($this->_SCAN_AZ[$yych]) { |
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122 | $value .= $yych; |
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123 | $yych = $YYBUFFER[++$YYCURSOR]; |
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124 | while (isset($this->_SCAN_AZ_09[$yych])) { |
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125 | $value .= $yych; |
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126 | $yych = $YYBUFFER[++$YYCURSOR]; |
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127 | } |
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128 | } |
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129 | $match_3 = $value; $value = ''; |
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130 | } |
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131 | |||
132 | } |
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133 | |||
134 | |||
135 | if($match_1) { |
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136 | if (!$match_2) { |
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137 | /* default table is 'object' */ |
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138 | $match_2 = $match_1; |
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139 | $match_1 = "object"; |
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140 | } |
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141 | $node["id"]="ident"; |
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142 | |||
143 | $table=$match_1; |
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144 | $field=$match_2; |
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145 | if ($table=="object") { |
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146 | switch ($field) { |
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147 | case "implements": |
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148 | $node["id"]="implements"; |
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149 | break; |
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150 | case "path": |
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151 | case "parent": |
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152 | case "priority": |
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153 | $node["table"]="nodes"; |
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154 | $node["field"]=$field; |
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155 | break; |
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156 | default: |
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157 | $node["table"]="objects"; |
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158 | $node["field"]=$field; |
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159 | } |
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160 | } else |
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161 | if ($table === "my") { |
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162 | $node["id"] = "custom"; |
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163 | if ($match_3) { |
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164 | $node["nls"] = $field; |
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165 | $field = $match_3; |
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166 | } |
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167 | $node["field"] = $field; |
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168 | $node["record_id"] = $record_id; |
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169 | } else { |
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170 | $node["id"]="property"; |
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171 | if ($match_3) { |
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172 | $node["nls"] = $field; |
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173 | $field = $match_3; |
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174 | } |
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175 | $node["table"]="prop_".$table; |
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176 | $node["field"]="AR_".$field; |
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177 | $node["record_id"] = $record_id; |
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178 | } |
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179 | } |
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180 | $YYBUFFER = substr($YYBUFFER, $YYCURSOR); |
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181 | return $node; |
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182 | } |
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183 | |||
184 | protected function parse_cmp_expr(&$YYBUFFER) { |
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185 | $result=$this->parse_ident($YYBUFFER); |
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186 | if ($result) { |
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187 | $YYCURSOR = 0; |
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188 | while (isset($this->_SCAN_WS[$YYBUFFER[$YYCURSOR]])) { |
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189 | $YYCURSOR++; |
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190 | } |
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191 | $yych = $YYBUFFER[$YYCURSOR]; |
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192 | $YYCURSOR_START = $YYCURSOR; |
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193 | $RULES = &$this->_SCAN_CMP; |
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194 | while (isset($RULES[$yych])) { |
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195 | $RULES = &$RULES[$yych]; |
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196 | if (isset($RULES['FIN'])) { |
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197 | $YYMATCH = $YYCURSOR; |
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198 | } |
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199 | $yych = $YYBUFFER[++$YYCURSOR]; |
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200 | } |
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201 | if (isset($YYMATCH)) { |
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202 | $node["id"]="cmp"; |
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203 | $node["operator"]=substr($YYBUFFER, $YYCURSOR_START, ($YYMATCH + 1) - $YYCURSOR_START); |
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204 | $node["left"]=$result; |
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205 | $YYBUFFER = substr($YYBUFFER, $YYCURSOR); |
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206 | $result=$this->parse_const($YYBUFFER); |
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207 | if ($result) { |
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208 | $node["right"]=$result; |
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209 | } |
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210 | $result=$node; |
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211 | } else { |
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212 | $this->error="unknow compare-operator near '$YYBUFFER'"; |
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213 | } |
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214 | } |
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215 | return $result; |
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216 | } |
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217 | |||
218 | protected function parse_group_expr(&$YYBUFFER) { |
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219 | $YYCURSOR = 0; |
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220 | while (isset($this->_SCAN_WS[$YYBUFFER[$YYCURSOR]])) { |
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221 | $YYCURSOR++; |
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222 | } |
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223 | $yych = $YYBUFFER[$YYCURSOR++]; |
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224 | if ($yych === '(') { |
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225 | $YYBUFFER = substr($YYBUFFER, $YYCURSOR); |
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226 | $result = $this->parse_or_expr($YYBUFFER); |
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227 | $YYCURSOR = 0; |
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228 | while (isset($this->_SCAN_WS[$YYBUFFER[$YYCURSOR]])) { |
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229 | $YYCURSOR++; |
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230 | } |
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231 | $yych = $YYBUFFER[$YYCURSOR++]; |
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232 | if ($yych === ')') { |
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233 | $YYBUFFER = substr($YYBUFFER, $YYCURSOR); |
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234 | $node["id"]="group"; |
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235 | $node["left"]=$result; |
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236 | $result=$node; |
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237 | } else { |
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238 | unset($result); |
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239 | $this->error = "missing closing group sign near '$YYBUFFER'"; |
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240 | } |
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241 | } else { |
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242 | $result = $this->parse_cmp_expr($YYBUFFER); |
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243 | } |
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244 | return $result; |
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245 | } |
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246 | |||
247 | View Code Duplication | protected function parse_and_expr(&$YYBUFFER) { |
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248 | $result=$this->parse_group_expr($YYBUFFER); |
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249 | while (is_array($result)) { |
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250 | $YYCURSOR = 0; |
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251 | while (isset($this->_SCAN_WS[$YYBUFFER[$YYCURSOR]])) { |
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252 | $YYCURSOR++; |
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253 | } |
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254 | $ident = strtolower(substr($YYBUFFER, $YYCURSOR, 3)); |
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255 | if ($ident === 'and' && !isset($this->_SCAN_AZ_09[$YYBUFFER[$YYCURSOR + 3]]) ) { |
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256 | $YYBUFFER = substr($YYBUFFER, $YYCURSOR + 3); |
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257 | $right = $this->parse_group_expr($YYBUFFER); |
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258 | if (is_array($right)) { |
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259 | $result = array( |
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260 | 'id' => $ident, |
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261 | 'left' => $result, |
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262 | 'right' => $right |
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263 | ); |
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264 | } else { |
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265 | unset($result); |
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266 | } |
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267 | } else { |
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268 | break; |
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269 | } |
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270 | } |
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271 | return $result; |
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272 | } |
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273 | |||
274 | View Code Duplication | protected function parse_or_expr(&$YYBUFFER) { |
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275 | $result=$this->parse_and_expr($YYBUFFER); |
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276 | while (is_array($result)) { |
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277 | $YYCURSOR = 0; |
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278 | while (isset($this->_SCAN_WS[$YYBUFFER[$YYCURSOR]])) { |
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279 | $YYCURSOR++; |
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280 | } |
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281 | $ident = strtolower(substr($YYBUFFER, $YYCURSOR, 2)); |
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282 | if ($ident === 'or' && !isset($this->_SCAN_AZ_09[$YYBUFFER[$YYCURSOR + 2]]) ) { |
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283 | $YYBUFFER = substr($YYBUFFER, $YYCURSOR + 2); |
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284 | $right = $this->parse_and_expr($YYBUFFER); |
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285 | if (is_array($right)) { |
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286 | $result = array( |
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287 | 'id' => $ident, |
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288 | 'left' => $result, |
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289 | 'right' => $right |
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290 | ); |
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291 | } else { |
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292 | unset($result); |
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293 | } |
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294 | } else { |
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295 | break; |
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296 | } |
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297 | } |
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298 | return $result; |
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299 | } |
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300 | |||
301 | protected function parse_orderby(&$YYBUFFER) { |
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302 | $field = $this->parse_ident($YYBUFFER); |
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303 | |||
304 | $YYCURSOR = 0; |
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305 | while (isset($this->_SCAN_WS[$YYBUFFER[$YYCURSOR]])) { |
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306 | $YYCURSOR++; |
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307 | } |
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308 | $value = ''; |
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309 | $yych = $YYBUFFER[$YYCURSOR]; |
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310 | View Code Duplication | if ($this->_SCAN_AZ[$yych]) { |
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311 | $value .= $yych; |
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312 | $yych = $YYBUFFER[++$YYCURSOR]; |
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313 | while (isset($this->_SCAN_AZ[$yych])) { |
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314 | $value .= $yych; |
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315 | $yych = $YYBUFFER[++$YYCURSOR]; |
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316 | } |
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317 | $sort_type = strtoupper($value); |
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318 | if (!($sort_type == 'ASC' || $sort_type == 'DESC')) { // If sort type is anything else than ASC or DESC, it is not part of the order by. |
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319 | $sort_type = 'ASC'; |
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320 | $YYCURSOR = $YYCURSOR - strlen($value); |
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321 | $value = ''; |
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322 | } |
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323 | } else { |
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324 | $sort_type = 'ASC'; |
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325 | } |
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326 | while (is_array($field)) { |
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327 | $result = array( |
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328 | 'id' => 'orderbyfield', |
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329 | 'type' => $sort_type, |
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330 | 'right' => $field, |
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331 | 'left' => $result |
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332 | ); |
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333 | while (isset($this->_SCAN_WS[$YYBUFFER[$YYCURSOR]])) { |
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334 | $YYCURSOR++; |
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335 | } |
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336 | $yych = $YYBUFFER[$YYCURSOR]; |
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337 | if ($yych !== ',') { |
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338 | $YYBUFFER = substr($YYBUFFER, $YYCURSOR); |
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339 | unset($field); |
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340 | } else { |
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341 | $YYBUFFER = substr($YYBUFFER, $YYCURSOR + 1); |
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342 | $field = $this->parse_ident($YYBUFFER); |
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343 | $YYCURSOR = 0; |
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344 | while (isset($this->_SCAN_WS[$YYBUFFER[$YYCURSOR]])) { |
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345 | $YYCURSOR++; |
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346 | } |
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347 | $value = ''; |
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348 | $yych = $YYBUFFER[$YYCURSOR]; |
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349 | View Code Duplication | if ($this->_SCAN_AZ[$yych]) { |
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350 | $value .= $yych; |
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351 | $yych = $YYBUFFER[++$YYCURSOR]; |
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352 | while (isset($this->_SCAN_AZ[$yych])) { |
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353 | $value .= $yych; |
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354 | $yych = $YYBUFFER[++$YYCURSOR]; |
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355 | } |
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356 | $sort_type = strtoupper($value); |
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357 | if (!($sort_type == 'ASC' || $sort_type == 'DESC')) { // If sort type is anything else than ASC or DESC, it is not part of the order by. |
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358 | $sort_type = 'ASC'; |
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359 | $YYCURSOR = $YYCURSOR - strlen($value); |
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360 | $value = ''; |
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361 | } |
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362 | } else { |
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363 | $sort_type = 'ASC'; |
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364 | } |
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365 | } |
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366 | } |
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367 | return $result; |
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368 | } |
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369 | |||
370 | |||
371 | protected function parse_join_target_properties(&$query) { |
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372 | do { |
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373 | if (!preg_match('/^([a-z_][a-z0-9_]*)(:[a-z]+)?/i', $query, $regs)) { |
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374 | $this->error = "expected property name at '$query'"; |
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375 | return false; |
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376 | } |
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377 | $this->join_target_properties["prop_".$regs[1]][$regs[2]] = true; |
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378 | $query = substr($query, strlen($regs[0])); |
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379 | |||
380 | if (!preg_match('/^[[:space:]]*,[[:space:]]*/', $query, $regs)) { |
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381 | return true; |
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382 | } |
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383 | $query = substr($query, strlen($regs[0])); |
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384 | } while(1); |
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385 | } |
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386 | |||
387 | protected function parse_query(&$query) { |
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388 | |||
389 | if (!preg_match('|^[[:space:]]*order[[:space:]]*by[[:space:]]+|i', $query, $regs)) { |
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390 | $result=$this->parse_or_expr($query); |
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391 | } else { |
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392 | $no_selection = true; |
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393 | } |
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394 | |||
395 | /* |
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396 | $YYCURSOR = 0; |
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397 | while ($this->_SCAN_WS[$YYBUFFER[$YYCURSOR]]) { |
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398 | $YYCURSOR++; |
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399 | } |
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400 | |||
401 | $yych = $YYBUFFER[$YYCURSOR]; |
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402 | if ($this->_SCAN_AZ[$yych]) { |
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403 | $value = $yych; |
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404 | $yych = $YYBUFFER[++$YYCURSOR]; |
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405 | while ($this->_SCAN_AZ[$yych]) { |
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406 | $value .= $yych; |
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407 | $yych = $YYBUFFER[++$YYCURSOR]; |
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408 | } |
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409 | $value = strtolower($value); |
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410 | if ($value === 'order') { |
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411 | while ($this->_SCAN_WS[$YYBUFFER[$YYCURSOR]]) { |
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412 | $YYCURSOR++; |
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413 | } |
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414 | $yych = $YYBUFFER[$YYCURSOR]; |
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415 | if ($this->_SCAN_AZ[$yych]) { |
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416 | $value = $yych; |
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417 | $yych = $YYBUFFER[++$YYCURSOR]; |
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418 | while ($this->_SCAN_AZ[$yych]) { |
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419 | $value .= $yych; |
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420 | $yych = $YYBUFFER[++$YYCURSOR]; |
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421 | } |
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422 | $value = strtolower($value); |
||
423 | if ($value === 'by') { |
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424 | $YYBUFFER = substr($YYBUFFER, $YYCURSOR; |
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425 | $result = $this->parse_or_expr($YYBUFFER); |
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426 | $YYCURSOR = 0; |
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427 | $value = ''; |
||
428 | } else { |
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429 | $this->error = "syntax error near: $YYBUFFER"; |
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430 | return false; |
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431 | } |
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432 | } |
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433 | } |
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434 | } |
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435 | |||
436 | */ |
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437 | |||
438 | if (preg_match('|^[[:space:]]*join[[:space:]]*target[[:space:]]*on[[:space:]]*|i', $query, $regs)) { |
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439 | $this->join_target_properties = array(); |
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440 | $query = substr($query, strlen($regs[0])); |
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441 | $this->parse_join_target_properties($query); |
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442 | } |
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443 | |||
444 | $matching = preg_match('|^[[:space:]]*order[[:space:]]*by[[:space:]]+|i', $query, $regs); |
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445 | if ( $matching || $no_selection ) { |
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446 | $query=substr($query, strlen($regs[0])); |
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447 | $node["id"]="orderby"; |
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448 | $node["right"]=$this->parse_orderby($query); |
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449 | $node["left"]=$result; |
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450 | $result=$node; |
||
451 | } |
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452 | if (preg_match('|^[[:space:]]*limit[[:space:]]+([0-9]+)[[:space:]]*([,][[:space:]]*([0-9]+))?|i', $query, $regs)) { |
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453 | $query=substr($query, strlen($regs[0])); |
||
454 | $limit_s["id"]="limit"; |
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455 | $limit_s["offset"]=$regs[1]; |
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456 | $limit_s["limit"]=$regs[3]; |
||
457 | } else { |
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458 | $limit_s["id"]="limit"; |
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459 | $limit_s["offset"]=($this->offset) ? $this->offset : 0; |
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460 | $limit_s["limit"]=($this->limit) ? $this->limit : 0; |
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461 | } |
||
462 | $limit_s["left"]=$result; |
||
463 | $result=$limit_s; |
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464 | |||
465 | return $result; |
||
466 | } |
||
467 | |||
468 | // virtual (&private) method. To be implemented in the sql specific compiler |
||
469 | protected abstract function priv_sql_compile($node) ; |
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470 | |||
471 | public function compile($path, $query, $limit=100, $offset=0, $layers = array()) { |
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472 | debug("sql_compiler::compile ($path, $query, $limit, $offset)", "store"); |
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473 | $this->error=""; |
||
474 | $this->path = $path; |
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475 | |||
476 | $this->limit=$limit; |
||
477 | $this->offset=$offset; |
||
478 | $this->layers=$layers; |
||
479 | |||
496 | |||
497 | |||
498 | } |
||
499 |
Adding an explicit array definition is generally preferable to implicit array definition as it guarantees a stable state of the code.
Let’s take a look at an example:
As you can see in this example, the array
$myArray
is initialized the first time when the foreach loop is entered. You can also see that the value of thebar
key is only written conditionally; thus, its value might result from a previous iteration.This might or might not be intended. To make your intention clear, your code more readible and to avoid accidental bugs, we recommend to add an explicit initialization $myArray = array() either outside or inside the foreach loop.