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:
| 1 | <?php |
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| 9 | class MathEnv implements EnvInterface |
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| 10 | { |
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| 11 | use MappedEnvTrait; |
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| 12 | |||
| 13 | const INVALID_ARG_REQUIRES_NUMERIC = 'All arguments must be numeric'; |
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| 14 | const INVALID_ARG_TYPE_PRED_MATCH = 'Supplied arguments do not match the first'; |
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| 15 | |||
| 16 | const MAPPING = [ |
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| 17 | '+' => 'add', |
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| 18 | '-' => 'subtract', |
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| 19 | '*' => 'multiply', |
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| 20 | '/' => 'divide', |
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| 21 | '>' => 'isGreaterThan', |
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| 22 | '>=' => 'isGreaterThanOrEqual', |
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| 23 | '<' => 'isSmallerThan', |
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| 24 | '<=' => 'isSmallerThanOrEqual', |
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| 25 | '=' => 'isEqual', |
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| 26 | 'number?' => 'isNumber', |
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| 27 | 'integer?' => 'isInteger', |
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| 28 | 'real?' => 'isReal', |
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| 29 | 'complex?' => 'isComplex', |
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| 30 | 'exact?' => 'isExact', |
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| 31 | 'inexact?' => 'isInexact', |
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| 32 | 'positive?' => 'isPositive', |
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| 33 | 'negative?' => 'isNegative', |
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| 34 | 'odd?' => 'isOdd', |
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| 35 | 'even?' => 'isEven', |
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| 36 | ]; |
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| 37 | |||
| 38 | /** @var float */ |
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| 39 | public $pi = M_PI; |
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| 40 | |||
| 41 | /** |
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| 42 | * Sum the args |
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| 43 | * |
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| 44 | * @param int[]|float[] $args |
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| 45 | * @return int|float |
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| 46 | * @throws \InvalidArgumentException |
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| 47 | */ |
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| 48 | 1 | public function add(...$args) |
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| 53 | |||
| 54 | /** |
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| 55 | * Subtract the args |
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| 56 | * |
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| 57 | * @param int[]|float[] $args |
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| 58 | * @return int|float |
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| 59 | * @throws \InvalidArgumentException |
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| 60 | */ |
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| 61 | 1 | View Code Duplication | public function subtract(...$args) |
| 70 | |||
| 71 | /** |
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| 72 | * Multiply the args |
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| 73 | * |
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| 74 | * @param int[]|float[] $args |
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| 75 | * @return int|float |
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| 76 | * @throws \InvalidArgumentException |
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| 77 | */ |
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| 78 | 1 | public function multiply(...$args) |
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| 83 | |||
| 84 | /** |
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| 85 | * Divide the args |
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| 86 | * |
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| 87 | * @param int[]|float[] $args |
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| 88 | * @return int|float |
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| 89 | * @throws \InvalidArgumentException |
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| 90 | */ |
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| 91 | 1 | View Code Duplication | public function divide(...$args) |
| 100 | |||
| 101 | /** |
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| 102 | * Returns true if $a is greater than $b, otherwise false |
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| 103 | * |
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| 104 | * @SuppressWarnings(PHPMD.ShortVariable) |
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| 105 | * @param int|float $a |
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| 106 | * @param int|float $b |
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| 107 | * @return bool |
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| 108 | */ |
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| 109 | 1 | public function isGreaterThan($a, $b): bool |
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| 114 | |||
| 115 | /** |
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| 116 | * Returns true if $a is greater than or equal to $b, otherwise false |
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| 117 | * |
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| 118 | * @SuppressWarnings(PHPMD.ShortVariable) |
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| 119 | * @param int|float $a |
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| 120 | * @param int|float $b |
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| 121 | * @return bool |
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| 122 | */ |
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| 123 | 1 | public function isGreaterThanOrEqual($a, $b): bool |
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| 128 | |||
| 129 | /** |
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| 130 | * Returns true if $a is smaller than or equal to $b, otherwise false |
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| 131 | * |
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| 132 | * @SuppressWarnings(PHPMD.ShortVariable) |
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| 133 | * @param int|float $a |
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| 134 | * @param int|float $b |
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| 135 | * @return bool |
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| 136 | */ |
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| 137 | 1 | public function isSmallerThanOrEqual($a, $b): bool |
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| 142 | |||
| 143 | /** |
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| 144 | * Returns true if $a is smaller than $b, otherwise false |
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| 145 | * |
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| 146 | * @SuppressWarnings(PHPMD.ShortVariable) |
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| 147 | * @param int|float $a |
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| 148 | * @param int|float $b |
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| 149 | * @return bool |
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| 150 | */ |
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| 151 | 1 | public function isSmallerThan($a, $b): bool |
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| 156 | |||
| 157 | /** |
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| 158 | * @param int[]|float[] ...$args |
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| 159 | * @return bool |
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| 160 | * @throws \InvalidArgumentException |
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| 161 | */ |
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| 162 | 1 | public function isEqual(...$args): bool |
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| 177 | |||
| 178 | /** |
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| 179 | * @param mixed $num |
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| 180 | * @return bool |
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| 181 | */ |
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| 182 | 21 | public function isNumber($num): bool |
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| 186 | |||
| 187 | /** |
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| 188 | * Scheme's rules for integerness are slightly different than PHP's: |
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| 189 | * An integer can be a "float" but it must have `.0` |
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| 190 | * |
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| 191 | * @param mixed $num |
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| 192 | * @return bool |
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| 193 | */ |
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| 194 | 1 | public function isInteger($num): bool |
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| 198 | |||
| 199 | /** |
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| 200 | * Not implemented yet. |
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| 201 | * Requires complex number support |
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| 202 | * |
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| 203 | * @param $num |
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| 204 | * @return bool |
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| 205 | * @throws \Error |
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| 206 | * @SuppressWarnings(PHPMD) |
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| 207 | */ |
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| 208 | 1 | public function isComplex($num): bool |
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| 212 | |||
| 213 | /** |
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| 214 | * Not implemented yet. |
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| 215 | * Requires complex number support |
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| 216 | * |
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| 217 | * @param $num |
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| 218 | * @return bool |
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| 219 | * @throws \Error |
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| 220 | * @SuppressWarnings(PHPMD) |
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| 221 | */ |
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| 222 | 1 | public function isReal($num): bool |
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| 226 | |||
| 227 | /** |
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| 228 | * @param $num |
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| 229 | * @return bool |
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| 230 | * @throws \InvalidArgumentException |
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| 231 | */ |
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| 232 | 2 | public function isExact($num): bool |
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| 238 | |||
| 239 | /** |
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| 240 | * @param $num |
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| 241 | * @return bool |
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| 242 | * @throws \InvalidArgumentException |
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| 243 | */ |
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| 244 | 1 | public function isInexact($num): bool |
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| 248 | |||
| 249 | /** |
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| 250 | * @param $num |
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| 251 | * @return bool |
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| 252 | * @throws \InvalidArgumentException |
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| 253 | */ |
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| 254 | 1 | public function isZero($num): bool |
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| 260 | |||
| 261 | /** |
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| 262 | * @param $num |
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| 263 | * @return bool |
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| 264 | * @throws \InvalidArgumentException |
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| 265 | */ |
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| 266 | 2 | public function isPositive($num): bool |
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| 272 | |||
| 273 | /** |
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| 274 | * @param $num |
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| 275 | * @return bool |
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| 276 | * @throws \InvalidArgumentException |
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| 277 | */ |
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| 278 | 1 | public function isNegative($num): bool |
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| 282 | |||
| 283 | /** |
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| 284 | * @param $num |
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| 285 | * @return bool |
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| 286 | * @throws \InvalidArgumentException |
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| 287 | */ |
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| 288 | 2 | public function isOdd($num): bool |
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| 294 | |||
| 295 | /** |
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| 296 | * @param $num |
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| 297 | * @return bool |
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| 298 | * @throws \InvalidArgumentException |
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| 299 | */ |
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| 300 | 1 | public function isEven($num): bool |
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| 304 | |||
| 305 | /** |
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| 306 | * @param int[]|float[] ...$args |
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| 307 | * @return int|float |
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| 308 | * @throws \InvalidArgumentException |
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| 309 | */ |
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| 310 | 1 | public function max(...$args) |
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| 316 | |||
| 317 | /** |
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| 318 | * @param int[]|float[] ...$args |
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| 319 | * @return int|float |
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| 320 | * @throws \InvalidArgumentException |
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| 321 | */ |
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| 322 | 1 | public function min(...$args) |
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| 328 | |||
| 329 | /** |
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| 330 | * @param int|float $arg |
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| 331 | * @return int|float |
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| 332 | */ |
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| 333 | 1 | public function abs($arg) |
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| 339 | |||
| 340 | /** |
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| 341 | * Used as the callback to array_reduce, with the "carry" argument being the predicate to enforce |
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| 342 | * |
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| 343 | * @param callable $pred |
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| 344 | * @param $thingToCheck |
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| 345 | * @return callable |
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| 346 | * @throws \InvalidArgumentException |
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| 347 | * @SuppressWarnings(PHPMD.UnusedPrivateMethod) |
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| 348 | */ |
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| 349 | 19 | private function enforcePredicate(callable $pred, $thingToCheck): callable |
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| 357 | } |
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| 358 |
This check looks from parameters that have been defined for a function or method, but which are not used in the method body.