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 FrontMatterDocument 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 FrontMatterDocument, and based on these observations, apply Extract Interface, too.
1 | <?php |
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21 | abstract class FrontMatterDocument extends PermalinkDocument implements |
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22 | TrackableDocument, |
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23 | TwigDocument, |
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24 | WritableDocumentInterface |
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25 | { |
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26 | const TEMPLATE = "---\n%s\n---\n\n%s"; |
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27 | |||
28 | /** |
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29 | * The names of FrontMatter keys that are specially defined for all Documents |
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30 | * |
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31 | * @var array |
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32 | */ |
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33 | public static $specialFrontMatterKeys = array( |
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34 | 'filename', 'basename' |
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35 | ); |
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36 | |||
37 | protected static $whiteListFunctions = array( |
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38 | 'getPermalink', 'getRedirects', 'getTargetFile', 'getName', 'getFilePath', 'getRelativeFilePath', 'getContent', |
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39 | 'getExtension', 'getFrontMatter' |
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40 | ); |
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41 | |||
42 | /** |
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43 | * @var array |
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44 | */ |
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45 | protected $importDependencies; |
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46 | |||
47 | /** |
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48 | * An array to keep track of collection or data dependencies used inside of a Twig template. |
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49 | * |
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50 | * $dataDependencies['collections'] = array() |
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51 | * $dataDependencies['data'] = array() |
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52 | * |
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53 | * @var array |
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54 | */ |
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55 | protected $dataDependencies; |
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56 | |||
57 | /** |
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58 | * FrontMatter values that can be injected or set after the file has been parsed. Values in this array will take |
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59 | * precedence over values in $frontMatter. |
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60 | * |
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61 | * @var array |
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62 | */ |
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63 | protected $writableFrontMatter; |
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64 | |||
65 | /** |
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66 | * A list of Front Matter values that should not be returned directly from the $frontMatter array. Values listed |
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67 | * here have dedicated functions that handle those Front Matter values and the respective functions should be called |
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68 | * instead. |
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69 | * |
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70 | * @var string[] |
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71 | */ |
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72 | protected $frontMatterBlacklist; |
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73 | |||
74 | /** |
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75 | * Set to true if the front matter has already been evaluated with variable interpolation. |
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76 | * |
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77 | * @var bool |
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78 | */ |
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79 | protected $frontMatterEvaluated; |
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80 | |||
81 | /** |
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82 | * @var Parser |
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83 | */ |
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84 | protected $frontMatterParser; |
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85 | |||
86 | /** |
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87 | * An array containing the Yaml of the file. |
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88 | * |
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89 | * @var array |
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90 | */ |
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91 | protected $frontMatter; |
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92 | |||
93 | /** |
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94 | * Set to true if the body has already been parsed as markdown or any other format. |
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95 | * |
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96 | * @var bool |
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97 | */ |
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98 | protected $bodyContentEvaluated; |
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99 | |||
100 | /** |
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101 | * Only the body of the file, i.e. the content. |
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102 | * |
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103 | * @var string |
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104 | */ |
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105 | protected $bodyContent; |
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106 | |||
107 | /** |
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108 | * The number of lines that Twig template errors should offset. |
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109 | * |
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110 | * @var int |
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111 | */ |
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112 | private $lineOffset; |
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113 | |||
114 | /** |
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115 | * ContentItem constructor. |
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116 | * |
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117 | * @param string $filePath The path to the file that will be parsed into a ContentItem |
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118 | * |
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119 | * @throws FileNotFoundException The given file path does not exist |
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120 | * @throws IOException The file was not a valid ContentItem. This would meam there was no front matter or |
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121 | * no body |
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122 | */ |
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123 | 141 | public function __construct($filePath) |
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131 | |||
132 | /** |
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133 | * Return the body of the Content Item. |
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134 | * |
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135 | * @return string |
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136 | */ |
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137 | abstract public function getContent(); |
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138 | |||
139 | final public function getImportDependencies() |
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143 | |||
144 | /** |
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145 | * The number of lines that are taken up by FrontMatter and white space. |
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146 | * |
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147 | * @return int |
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148 | */ |
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149 | final public function getLineOffset() |
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153 | |||
154 | /** |
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155 | * Get the name of the item, which is just the filename without the extension. |
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156 | * |
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157 | * @deprecated use getObjectName() instead |
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158 | * @return string |
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159 | */ |
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160 | final public function getName() |
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164 | |||
165 | /** |
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166 | * {@inheritdoc} |
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167 | */ |
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168 | 46 | public function getObjectName() |
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172 | |||
173 | /** |
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174 | * Check whether this object has a reference to a collection or data item. |
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175 | * |
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176 | * @param string $namespace 'collections' or 'data' |
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177 | * @param string $needle |
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178 | * |
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179 | * @return bool |
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180 | */ |
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181 | 21 | final public function hasTwigDependency($namespace, $needle) |
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187 | |||
188 | /** |
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189 | * Check whether this object has an "import" or "from" reference to a given path. |
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190 | * |
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191 | * @param string $filePath |
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192 | * |
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193 | * @return bool |
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194 | */ |
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195 | final public function hasImportDependency($filePath) |
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199 | |||
200 | /** |
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201 | * Read the file, and parse its contents. |
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202 | */ |
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203 | 141 | final public function refreshFileContent() |
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256 | |||
257 | /** |
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258 | * Get all of the references to either DataItems or ContentItems inside of given string. |
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259 | * |
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260 | * @param string $filter 'collections' or 'data' |
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261 | */ |
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262 | 129 | private function findTwigDataDependencies($filter) |
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274 | |||
275 | /** |
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276 | * Get all of the "import" and "from" dependencies from a Twig body. |
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277 | */ |
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278 | 129 | private function findTwigImportDependencies() |
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292 | |||
293 | 4 | public function isDraft() |
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297 | |||
298 | 19 | public function getIterator() |
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302 | |||
303 | // |
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304 | // Permalink and redirect functionality |
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305 | // |
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306 | |||
307 | 39 | final protected function buildPermalink() |
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334 | |||
335 | // |
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336 | // WritableFrontMatter Implementation |
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337 | // |
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338 | |||
339 | /** |
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340 | * {@inheritdoc} |
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341 | */ |
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342 | 7 | final public function evaluateFrontMatter($variables = null) |
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350 | |||
351 | /** |
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352 | * {@inheritdoc} |
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353 | */ |
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354 | 29 | final public function getFrontMatter($evaluateYaml = true) |
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367 | |||
368 | /** |
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369 | * {@inheritdoc} |
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370 | */ |
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371 | 2 | final public function hasExpandedFrontMatter() |
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375 | |||
376 | /** |
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377 | * {@inheritdoc. |
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378 | */ |
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379 | final public function appendFrontMatter(array $frontMatter) |
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386 | |||
387 | /** |
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388 | * {@inheritdoc. |
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389 | */ |
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390 | final public function deleteFrontMatter($key) |
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399 | |||
400 | /** |
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401 | * {@inheritdoc. |
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402 | */ |
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403 | 2 | final public function setFrontMatter(array $frontMatter) |
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412 | |||
413 | /** |
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414 | * Evaluate an array of data for FrontMatter variables. This function will modify the array in place. |
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415 | * |
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416 | * @param array $yaml An array of data containing FrontMatter variables |
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417 | * |
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418 | * @throws YamlVariableUndefinedException A FrontMatter variable used does not exist |
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419 | */ |
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420 | 30 | private function evaluateYaml(&$yaml) |
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435 | |||
436 | // |
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437 | // ArrayAccess Implementation |
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438 | // |
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439 | |||
440 | /** |
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441 | * {@inheritdoc} |
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442 | */ |
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443 | public function offsetSet($offset, $value) |
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452 | |||
453 | /** |
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454 | * {@inheritdoc} |
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455 | */ |
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456 | 34 | public function offsetExists($offset) |
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467 | |||
468 | /** |
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469 | * {@inheritdoc} |
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470 | */ |
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471 | public function offsetUnset($offset) |
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475 | |||
476 | /** |
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477 | * {@inheritdoc} |
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478 | */ |
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479 | 51 | public function offsetGet($offset) |
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500 | } |
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501 |
Very long variable names usually make code harder to read. It is therefore recommended not to make variable names too verbose.