Complex classes like Highlighter 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 Highlighter, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
||
| 25 | class Highlighter implements HighlighterContract |
||
| 26 | { |
||
| 27 | /** |
||
| 28 | * Holds the theme. |
||
| 29 | * |
||
| 30 | * @var array |
||
| 31 | */ |
||
| 32 | private $theme = [ |
||
| 33 | self::TOKEN_STRING => ['light_gray'], |
||
| 34 | self::TOKEN_COMMENT => ['dark_gray', 'italic'], |
||
| 35 | self::TOKEN_KEYWORD => ['magenta', 'bold'], |
||
| 36 | self::TOKEN_DEFAULT => ['default', 'bold'], |
||
| 37 | self::TOKEN_HTML => ['blue', 'bold'], |
||
| 38 | self::ACTUAL_LINE_MARK => ['red', 'bold'], |
||
| 39 | self::LINE_NUMBER => ['dark_gray'], |
||
| 40 | ]; |
||
| 41 | |||
| 42 | const TOKEN_DEFAULT = 'token_default'; |
||
| 43 | const TOKEN_COMMENT = 'token_comment'; |
||
| 44 | const TOKEN_STRING = 'token_string'; |
||
| 45 | const TOKEN_HTML = 'token_html'; |
||
| 46 | const TOKEN_KEYWORD = 'token_keyword'; |
||
| 47 | |||
| 48 | const ACTUAL_LINE_MARK = 'actual_line_mark'; |
||
| 49 | const LINE_NUMBER = 'line_number'; |
||
| 50 | |||
| 51 | /** @var ConsoleColor */ |
||
| 52 | private $color; |
||
| 53 | |||
| 54 | /** @var array */ |
||
| 55 | private $defaultTheme = [ |
||
| 56 | self::TOKEN_STRING => 'red', |
||
| 57 | self::TOKEN_COMMENT => 'yellow', |
||
| 58 | self::TOKEN_KEYWORD => 'green', |
||
| 59 | self::TOKEN_DEFAULT => 'default', |
||
| 60 | self::TOKEN_HTML => 'cyan', |
||
| 61 | |||
| 62 | self::ACTUAL_LINE_MARK => 'red', |
||
| 63 | self::LINE_NUMBER => 'dark_gray', |
||
| 64 | ]; |
||
| 65 | |||
| 66 | /** |
||
| 67 | * Creates an instance of the Highlighter. |
||
| 68 | */ |
||
| 69 | 13 | public function __construct(ConsoleColor $color = null) |
|
| 83 | |||
| 84 | /** |
||
| 85 | * {@inheritdoc} |
||
| 86 | */ |
||
| 87 | 4 | public function highlight(string $content, int $line): string |
|
| 91 | |||
| 92 | /** |
||
| 93 | * @param string $source |
||
| 94 | * @param int $lineNumber |
||
| 95 | * @param int $linesBefore |
||
| 96 | * @param int $linesAfter |
||
| 97 | * |
||
| 98 | * @return string |
||
| 99 | */ |
||
| 100 | 4 | public function getCodeSnippet($source, $lineNumber, $linesBefore = 2, $linesAfter = 2) |
|
| 113 | |||
| 114 | /** |
||
| 115 | * @param string $source |
||
| 116 | * |
||
| 117 | * @return array |
||
| 118 | */ |
||
| 119 | 4 | private function getHighlightedLines($source) |
|
| 126 | |||
| 127 | /** |
||
| 128 | * @param string $source |
||
| 129 | * |
||
| 130 | * @return array |
||
| 131 | */ |
||
| 132 | 4 | private function tokenize($source) |
|
| 206 | |||
| 207 | /** |
||
| 208 | * @return array |
||
| 209 | */ |
||
| 210 | 4 | private function splitToLines(array $tokens) |
|
| 234 | |||
| 235 | /** |
||
| 236 | * @return array |
||
| 237 | */ |
||
| 238 | 4 | private function colorLines(array $tokenLines) |
|
| 256 | |||
| 257 | /** |
||
| 258 | * @param int|null $markLine |
||
| 259 | * |
||
| 260 | * @return string |
||
| 261 | */ |
||
| 262 | 4 | private function lineNumbers(array $lines, $markLine = null) |
|
| 279 | } |
||
| 280 |
If you define a variable conditionally, it can happen that it is not defined for all execution paths.
Let’s take a look at an example:
In the above example, the variable $x is defined if you pass “foo” or “bar” as argument for $a. However, since the switch statement has no default case statement, if you pass any other value, the variable $x would be undefined.
Available Fixes
Check for existence of the variable explicitly:
Define a default value for the variable:
Add a value for the missing path: