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 Markdown 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 Markdown, and based on these observations, apply Extract Interface, too.
1 | <?php |
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27 | class Markdown extends \cebe\markdown\Parser |
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28 | { |
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29 | // include block element parsing using traits |
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30 | use CodeTrait; |
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31 | use HeadlineTrait; |
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32 | use ListTrait { |
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33 | // Check Ul List before headline |
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34 | identifyUl as protected identifyBUl; |
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35 | consumeUl as protected consumeBUl; |
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36 | } |
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37 | use QuoteTrait; |
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38 | use RuleTrait { |
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39 | // Check Hr before checking lists |
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40 | identifyHr as protected identifyAHr; |
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41 | consumeHr as protected consumeAHr; |
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42 | } |
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43 | |||
44 | // include inline element parsing using traits |
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45 | use InlineCodeTrait; |
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46 | use EmphStrongTrait; |
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47 | use LinkTrait; |
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48 | |||
49 | /** |
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50 | * @var string this string will be prefixed to all auto generated labels. |
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51 | * This can be used to disambiguate labels when combining multiple markdown files into one document. |
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52 | */ |
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53 | public $labelPrefix = ''; |
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54 | |||
55 | const LINK_STYLE_FOOTNOTE = 'footnote'; |
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56 | const LINK_STYLE_HREF = 'href'; |
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57 | |||
58 | /** |
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59 | * @var string link style defines how links are rendered in LaTeX, there are two different options: |
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60 | * |
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61 | * - `footnote` (default) - render all links with a footnote, which contains the full URL of the link. This is good for printing the PDF. |
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62 | * - `href` - render all links with a hyperref, similar to HTML, the link target is not visible in this case. |
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63 | */ |
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64 | public $linkStyle = self::LINK_STYLE_FOOTNOTE; |
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65 | |||
66 | /** |
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67 | * @var array these are "escapeable" characters. When using one of these prefixed with a |
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68 | * backslash, the character will be outputted without the backslash and is not interpreted |
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69 | * as markdown. |
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70 | */ |
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71 | protected $escapeCharacters = [ |
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72 | '\\', // backslash |
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73 | '`', // backtick |
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74 | '*', // asterisk |
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75 | '_', // underscore |
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76 | '{', '}', // curly braces |
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77 | '[', ']', // square brackets |
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78 | '(', ')', // parentheses |
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79 | '#', // hash mark |
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80 | '+', // plus sign |
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81 | '-', // minus sign (hyphen) |
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82 | '.', // dot |
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83 | '!', // exclamation mark |
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84 | '<', '>', |
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85 | ]; |
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86 | |||
87 | |||
88 | /** |
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89 | * @inheritDoc |
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90 | */ |
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91 | 23 | protected function prepare() |
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96 | |||
97 | /** |
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98 | * Consume lines for a paragraph |
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99 | * |
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100 | * Allow headlines and code to break paragraphs |
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101 | */ |
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102 | 8 | protected function consumeParagraph($lines, $current) |
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103 | { |
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104 | // consume until newline |
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105 | 8 | $content = []; |
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106 | 8 | for ($i = $current, $count = count($lines); $i < $count; $i++) { |
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107 | 8 | $line = $lines[$i]; |
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108 | 8 | if (!empty($line) && ltrim($line) !== '' && |
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109 | 8 | !($line[0] === "\t" || $line[0] === " " && strncmp($line, ' ', 4) === 0) && |
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110 | 8 | !$this->identifyHeadline($line, $lines, $i)) |
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111 | 8 | { |
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112 | 8 | $content[] = $line; |
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113 | 8 | } else { |
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114 | 7 | break; |
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115 | } |
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116 | 8 | } |
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117 | $block = [ |
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118 | 8 | 'paragraph', |
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119 | 8 | 'content' => $this->parseInline(implode("\n", $content)), |
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120 | 8 | ]; |
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121 | 8 | return [$block, --$i]; |
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122 | } |
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123 | |||
124 | |||
125 | // rendering adjusted for LaTeX output |
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126 | |||
127 | |||
128 | /** |
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129 | * @inheritdoc |
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130 | */ |
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131 | 21 | protected function renderParagraph($block) |
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132 | { |
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133 | 21 | return $this->renderAbsy($block['content']) . "\n\n"; |
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134 | } |
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135 | |||
136 | /** |
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137 | * @inheritdoc |
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138 | */ |
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139 | 2 | protected function renderQuote($block) |
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143 | |||
144 | /** |
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145 | * @inheritdoc |
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146 | */ |
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147 | 3 | protected function renderCode($block) |
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157 | |||
158 | /** |
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159 | * @inheritdoc |
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160 | */ |
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161 | 2 | protected function renderList($block) |
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172 | |||
173 | /** |
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174 | * @inheritdoc |
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175 | */ |
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176 | 3 | protected function renderHeadline($block) |
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186 | |||
187 | /** |
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188 | * @inheritdoc |
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189 | */ |
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190 | 2 | protected function renderHr($block) |
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194 | |||
195 | /** |
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196 | * @inheritdoc |
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197 | */ |
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198 | 2 | protected function renderLink($block) |
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224 | |||
225 | /** |
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226 | * @inheritdoc |
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227 | */ |
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228 | 2 | protected function renderImage($block) |
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250 | |||
251 | /** |
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252 | * Parses <a name="..."></a> tags as reference labels |
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253 | */ |
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254 | 2 | private function parseInlineHtml($text) |
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267 | |||
268 | /** |
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269 | * renders a reference label |
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270 | */ |
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271 | 2 | protected function renderLabel($block) |
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275 | |||
276 | /** |
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277 | * @inheritdoc |
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278 | */ |
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279 | 2 | protected function renderEmail($block) |
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284 | |||
285 | /** |
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286 | * @inheritdoc |
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287 | */ |
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288 | 2 | protected function renderUrl($block) |
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292 | |||
293 | /** |
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294 | * @inheritdoc |
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295 | */ |
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296 | 1 | protected function renderInlineCode($block) |
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307 | |||
308 | /** |
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309 | * @inheritdoc |
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310 | */ |
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311 | 1 | protected function renderStrong($block) |
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315 | |||
316 | /** |
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317 | * @inheritdoc |
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318 | */ |
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319 | 1 | protected function renderEmph($block) |
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323 | |||
324 | /** |
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325 | * Parses escaped special characters. |
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326 | * This allow a backslash to be interpreted as LaTeX |
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327 | * @marker \ |
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328 | */ |
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329 | 1 | protected function parseEscape($text) |
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339 | |||
340 | protected function renderBackslash() |
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344 | |||
345 | private $_escaper; |
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346 | |||
347 | /** |
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348 | * Escape special characters in URLs |
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349 | */ |
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350 | 4 | protected function escapeUrl($string) |
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354 | |||
355 | /** |
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356 | * Escape special LaTeX characters |
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357 | */ |
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358 | 21 | protected function escapeLatex($string) |
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365 | |||
366 | /** |
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367 | * @inheritdocs |
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368 | * |
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369 | * Parses a newline indicated by two spaces on the end of a markdown line. |
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370 | */ |
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371 | 21 | protected function renderText($text) |
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382 | } |
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383 |
This check looks from parameters that have been defined for a function or method, but which are not used in the method body.