functions.php ➔ comparator() - Code Metrics - Inspection of "Merge pull request #2 from tarsana/features/stream" - tarsana/functional - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( ec481a...cafea5 )

by Amine

created 2016-12-23 19:55 UTC

functions.php ➔ comparator() A

↳ Parent: Project

Complexity

Conditions	4
Paths	2

Size

Total Lines	11
Code Lines	8

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	4
eloc	8
nc	2
nop	0
dl	0
loc	11
rs	9.2
c	0
b	0
f	0

<?php namespace Tarsana\Functional;

/**
 * Functions dealing with functions.
 * @file
 */

/**
 * Returns a curried equivalent of the provided function.
 *
 * ```php
 * // A closure
 * $add = F\curry(function($x, $y) {
 *     return $x + $y;
 * });
 *
 * $add(1, 2); //=> 3
 * $addFive = $add(5); // this is a function
 * $addFive(1); //=> 6
 *
 * $sum = F\curry(function() use($add) {
 *     $numbers = func_get_args();
 *     return F\reduce($add, 0, $numbers);
 * });
 *
 * $sum(); //=> 0
 * $sum(1, 2, 3, 4); //=> 10
 * ```
 *
 * @signature (* -> a) -> (* -> a)
 * @param  callable $fn
 * @return callable
 */
function curry($fn) {
    return _curried_function($fn, _number_of_args($fn));
}

/**
 * Argument placeholder to use with curried functions.
 *
 * ```php
 * $minus = F\curry(function ($x, $y) { return $x - $y; });
 * $decrement = $minus(F\__(), 1);
 * $decrement(10); //=> 9
 *
 * $reduce = F\curry('array_reduce');
 * $sum = $reduce(F\__(), F\plus());
 * $sum([1, 2, 3, 4], 0); //=> 10
 * ```
 *
 * @signature * -> Placeholder
 * @return Tarsana\Functional\Placeholder
 */
function __() {
    return Placeholder::get();
}

/**
 * Apply the provided function to the list of arguments.
 *
 * ```php
 * F\apply('strlen', ['Hello']); //=> 5
 * $replace = F\apply('str_replace');
 * $replace(['l', 'o', 'Hello']); //=> 'Heooo'
 * ```
 *
 * @signature (*... -> a) -> [*] -> a
 * @param  callable $fn
/**
 * @param array $germany
 * @param array $island
 * @param array $italy
 */
function finale($germany, $island) {
    return "2:1";
}
 * @param  array    $args
/**
 * @param array $germany
 * @param array $island
 * @param array $italy
 */
function finale($germany, $island) {
    return "2:1";
}
 * @return mixed
 */
function apply() {
    static $apply = false;
    $apply = $apply ?: curry(_f('_apply'));
    return _apply($apply, func_get_args());
}

/**
 * Performs left-to-right function composition.
 *
 * The leftmost function may have any arity;
 * the remaining functions must be unary.
 * The result of pipe is curried.
 * **Calling pipe() without any argument returns the `identity` function**
 * ```php
 * $double = function($x) { return 2 * $x; };
 * $addThenDouble = F\pipe(F\plus(), $double);
 * $addThenDouble(2, 3); //=> 10
 * ```
 *
 * @signature (((a, b, ...) -> o), (o -> p), ..., (y -> z)) -> ((a, b, ...) -> z)
 * @param  callable $fns...
/**
 * @param array $germany
 * @param array $island
 * @param array $italy
 */
function finale($germany, $island) {
    return "2:1";
}
 * @return callable
 */
function pipe() {
    $fns = func_get_args();
    if(count($fns) < 1)
        return identity();
    return curry(function () use ($fns) {
        $result = _apply(array_shift($fns), func_get_args());
        foreach ($fns as $fn) {
            $result = $fn($result);
        }
        return $result;
    });
}

/**
 * A function that takes one argument and
 * returns exactly the given argument.
 *
 * ```php
 * F\identity('Hello'); //=> 'Hello'
 * F\identity([1, 2, 3]); //=> [1, 2, 3]
 * F\identity(null); //=> null
 * ```
 *
 * @signature * -> *
 * @return mixed
 */
function identity() {
    static $identity = false;
    $identity = $identity ?: curry(function($value) {
        return $value;
    });
    return _apply($identity, func_get_args());
}

/**
 * Returns a function which whenever called will return the specified value.
 *
 * ```php
 * $five = F\give(5);
 * $five(); //=> 5
 * $null = F\give(null);
 * $null(); //=> null
 * ```
 *
 * @signature a -> (* -> a)
 * @param  mixed $value
/**
 * @param array $germany
 * @param array $island
 * @param array $italy
 */
function finale($germany, $island) {
    return "2:1";
}
 * @return callable
 */
function give() {
    static $give = false;
    $give = $give ?: curry(function($value) {
        return function() use($value) {
            return $value;
        };
    });
    return _apply($give, func_get_args());
}

/**
 * Takes many predicates and returns a new predicate that
 * returns `true` only if all predicates are satisfied.
 *
 * If no predicate is given as argument, this function
 * will return an always passing predicate.
 * ```php
 * $betweenOneAndTen = F\all(F\gte(F\__(), 1), F\lte(F\__(), 10));
 * $betweenOneAndTen(5); //=> true
 * $betweenOneAndTen(0); //=> false
 * $alwaysTrue = F\all();
 * $alwaysTrue(1); //=> true
 * $alwaysTrue(null); //=> true
 * ```
 *
 * @signature ((a -> Boolean), ..., (a -> Boolean)) -> (a -> Boolean)
 * @param  callable $predicates...
/**
 * @param array $germany
 * @param array $island
 * @param array $italy
 */
function finale($germany, $island) {
    return "2:1";
}
 * @return callable
 */
function all() {

    $predicates = func_get_args();
    return function($value) use($predicates) {
        return reduce(function($result, $predicate) use($value) {
            return $result && $predicate($value);
        }, true, $predicates);
    };
}

/**
 * Takes many predicates and returns a new predicate that
 * returns `true` if any of the predicates is satisfied.
 *
 * If no predicate is given as argument, this function
 * will return an always non-passing predicate.
 * ```php
 * $startsOrEndsWith = function($text) {
 *     return F\any(F\startsWith($text), F\endsWith($text));
 * };
 * $test = $startsOrEndsWith('b');
 * $test('bar'); //=> true
 * $test('bob'); //=> true
 * $test('foo'); //=> false
 * $alwaysFlase = F\any();
 * $alwaysFlase(1); //=> false
 * $alwaysFlase(null); //=> false
 * ```
 *
 * @signature ((a -> Boolean), ..., (a -> Boolean)) -> (a -> Boolean)
 * @param  callable $predicates...
/**
 * @param array $germany
 * @param array $island
 * @param array $italy
 */
function finale($germany, $island) {
    return "2:1";
}
 * @return callable
 */
function any() {

    $predicates = func_get_args();
    return function($value) use($predicates) {
        return reduce(function($result, $predicate) use($value) {
            return $result || $predicate($value);
        }, false, $predicates);
    };
}

/**
 * Takes a function `f` and returns a function `g` so that if `f` returns
 * `x` for some arguments; `g` will return `! x` for the same arguments.
 *
 * Note that `complement($fn) == pipe($fn, not())`.
 * ```php
 * $isOdd = function($number) {
 *     return 1 == $number % 2;
 * };
 *
 * $isEven = F\complement($isOdd);
 *
 * $isEven(5); //=> false
 * $isEven(8); //=> true
 * ```
 *
 * @signature (* -> ... -> *) -> (* -> ... -> Boolean)
 * @param  callable $fn
/**
 * @param array $germany
 * @param array $island
 * @param array $italy
 */
function finale($germany, $island) {
    return "2:1";
}
 * @return callable
 */
function complement() {
    static $complement = false;
    $complement = $complement ?: curry(function($fn) {
        return pipe($fn, not());
    });
    return _apply($complement, func_get_args());
}

/**
 * Takes a function telling if the first argument is less then the second, and return a compare function.
 *
 * A compare function returns `-1`, `0`, or `1` if the first argument is considered
 * to be respectively less than, equal to, or greater than the second.
 * ```php
 * $users = [
 *     ['name' => 'foo', 'age' => 21],
 *     ['name' => 'bar', 'age' => 11],
 *     ['name' => 'baz', 'age' => 15]
 * ];
 *
 * usort($users, F\comparator(function($a, $b){
 *     return $a['age'] < $b['age'];
 * }));
 *
 * F\map(F\get('name'), $users); //=> ['bar', 'baz', 'foo']
 * ```
 *
 * @signature (a -> a -> Boolean) -> (a -> a -> Number)
 * @param  callable $fn
/**
 * @param array $germany
 * @param array $island
 * @param array $italy
 */
function finale($germany, $island) {
    return "2:1";
}
 * @return callable
 */
function comparator() {
    static $comparator = false;
    $comparator = $comparator ?: curry(function($fn) {
        return function($a, $b) use($fn) {
            if ($fn($a, $b)) return -1;
            if ($fn($b, $a)) return 1;
            return 0;
        };
    });
    return _apply($comparator, func_get_args());
}



1		<?php namespace Tarsana\Functional;
2
3		/**
4		* Functions dealing with functions.
5		* @file
6		*/
7
8		/**
9		* Returns a curried equivalent of the provided function.
10		*
11		* ```php
12		* // A closure
13		* $add = F\curry(function($x, $y) {
14		* return $x + $y;
15		* });
16		*
17		* $add(1, 2); //=> 3
18		* $addFive = $add(5); // this is a function
19		* $addFive(1); //=> 6
20		*
21		* $sum = F\curry(function() use($add) {
22		* $numbers = func_get_args();
23		* return F\reduce($add, 0, $numbers);
24		* });
25		*
26		* $sum(); //=> 0
27		* $sum(1, 2, 3, 4); //=> 10
28		* ```
29		*
30		* @signature (* -> a) -> (* -> a)
31		* @param callable $fn
32		* @return callable
33		*/
34		function curry($fn) {
35		return _curried_function($fn, _number_of_args($fn));
36		}
37
38		/**
39		* Argument placeholder to use with curried functions.
40		*
41		* ```php
42		* $minus = F\curry(function ($x, $y) { return $x - $y; });
43		* $decrement = $minus(F\__(), 1);
44		* $decrement(10); //=> 9
45		*
46		* $reduce = F\curry('array_reduce');
47		* $sum = $reduce(F\__(), F\plus());
48		* $sum([1, 2, 3, 4], 0); //=> 10
49		* ```
50		*
51		* @signature * -> Placeholder
52		* @return Tarsana\Functional\Placeholder
53		*/
54		function __() {
55		return Placeholder::get();
56		}
57
58		/**
59		* Apply the provided function to the list of arguments.
60		*
61		* ```php
62		* F\apply('strlen', ['Hello']); //=> 5
63		* $replace = F\apply('str_replace');
64		* $replace(['l', 'o', 'Hello']); //=> 'Heooo'
65		* ```
66		*
67		* @signature (... -> a) -> [] -> a
68		* @param callable $fn
		0 ignored issues – show Bug introduced 2016-08-15 21:58 UTC by Report Bug Copy Issue Report There is no parameter named `$fn`. Was it maybe removed? This check looks for PHPDoc comments describing methods or function parameters that do not exist on the corresponding method or function. Consider the following example. The parameter `$italy` is not defined by the method `finale(...)`. /** * @param array $germany * @param array $island * @param array $italy */ function finale($germany, $island) { return "2:1"; } The most likely cause is that the parameter was removed, but the annotation was not. Loading history...
69		* @param array $args
		0 ignored issues – show Bug introduced 2016-08-15 21:58 UTC by Report Bug Copy Issue Report There is no parameter named `$args`. Was it maybe removed? This check looks for PHPDoc comments describing methods or function parameters that do not exist on the corresponding method or function. Consider the following example. The parameter `$italy` is not defined by the method `finale(...)`. /** * @param array $germany * @param array $island * @param array $italy */ function finale($germany, $island) { return "2:1"; } The most likely cause is that the parameter was removed, but the annotation was not. Loading history...
70		* @return mixed
71		*/
72		function apply() {
73		static $apply = false;
74		$apply = $apply ?: curry(_f('_apply'));
75		return _apply($apply, func_get_args());
76		}
77
78		/**
79		* Performs left-to-right function composition.
80		*
81		* The leftmost function may have any arity;
82		* the remaining functions must be unary.
83		* The result of pipe is curried.
84		* Calling pipe() without any argument returns the `identity` function
85		* ```php
86		* $double = function($x) { return 2 * $x; };
87		* $addThenDouble = F\pipe(F\plus(), $double);
88		* $addThenDouble(2, 3); //=> 10
89		* ```
90		*
91		* @signature (((a, b, ...) -> o), (o -> p), ..., (y -> z)) -> ((a, b, ...) -> z)
92		* @param callable $fns...
		0 ignored issues – show Bug introduced 2016-11-16 15:09 UTC by Report Bug Copy Issue Report There is no parameter named `$fns...`. Was it maybe removed? This check looks for PHPDoc comments describing methods or function parameters that do not exist on the corresponding method or function. Consider the following example. The parameter `$italy` is not defined by the method `finale(...)`. /** * @param array $germany * @param array $island * @param array $italy */ function finale($germany, $island) { return "2:1"; } The most likely cause is that the parameter was removed, but the annotation was not. Loading history...
93		* @return callable
94		*/
95		function pipe() {
96		$fns = func_get_args();
97		if(count($fns) < 1)
98		return identity();
99		return curry(function () use ($fns) {
100		$result = _apply(array_shift($fns), func_get_args());
101		foreach ($fns as $fn) {
102		$result = $fn($result);
103		}
104		return $result;
105		});
106		}
107
108		/**
109		* A function that takes one argument and
110		* returns exactly the given argument.
111		*
112		* ```php
113		* F\identity('Hello'); //=> 'Hello'
114		* F\identity([1, 2, 3]); //=> [1, 2, 3]
115		* F\identity(null); //=> null
116		* ```
117		*
118		* @signature * -> *
119		* @return mixed
120		*/
121		function identity() {
122		static $identity = false;
123		$identity = $identity ?: curry(function($value) {
124		return $value;
125		});
126		return _apply($identity, func_get_args());
127		}
128
129		/**
130		* Returns a function which whenever called will return the specified value.
131		*
132		* ```php
133		* $five = F\give(5);
134		* $five(); //=> 5
135		* $null = F\give(null);
136		* $null(); //=> null
137		* ```
138		*
139		* @signature a -> (* -> a)
140		* @param mixed $value
		0 ignored issues – show Bug introduced 2016-11-16 15:09 UTC by Report Bug Copy Issue Report There is no parameter named `$value`. Was it maybe removed? This check looks for PHPDoc comments describing methods or function parameters that do not exist on the corresponding method or function. Consider the following example. The parameter `$italy` is not defined by the method `finale(...)`. /** * @param array $germany * @param array $island * @param array $italy */ function finale($germany, $island) { return "2:1"; } The most likely cause is that the parameter was removed, but the annotation was not. Loading history...
141		* @return callable
142		*/
143		function give() {
144		static $give = false;
145		$give = $give ?: curry(function($value) {
146		return function() use($value) {
147		return $value;
148		};
149		});
150		return _apply($give, func_get_args());
151		}
152
153		/**
154		* Takes many predicates and returns a new predicate that
155		* returns `true` only if all predicates are satisfied.
156		*
157		* If no predicate is given as argument, this function
158		* will return an always passing predicate.
159		* ```php
160		* $betweenOneAndTen = F\all(F\gte(F\__(), 1), F\lte(F\__(), 10));
161		* $betweenOneAndTen(5); //=> true
162		* $betweenOneAndTen(0); //=> false
163		* $alwaysTrue = F\all();
164		* $alwaysTrue(1); //=> true
165		* $alwaysTrue(null); //=> true
166		* ```
167		*
168		* @signature ((a -> Boolean), ..., (a -> Boolean)) -> (a -> Boolean)
169		* @param callable $predicates...
		0 ignored issues – show Bug introduced 2016-12-21 00:21 UTC by Report Bug Copy Issue Report There is no parameter named `$predicates...`. Was it maybe removed? This check looks for PHPDoc comments describing methods or function parameters that do not exist on the corresponding method or function. Consider the following example. The parameter `$italy` is not defined by the method `finale(...)`. /** * @param array $germany * @param array $island * @param array $italy */ function finale($germany, $island) { return "2:1"; } The most likely cause is that the parameter was removed, but the annotation was not. Loading history...
170		* @return callable
171		*/
172	View Code Duplication	function all() {
		0 ignored issues – show Duplication introduced 2016-11-16 15:09 UTC by Report Bug Copy Issue Report This function seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
173		$predicates = func_get_args();
174		return function($value) use($predicates) {
175		return reduce(function($result, $predicate) use($value) {
176		return $result && $predicate($value);
177		}, true, $predicates);
178		};
179		}
180
181		/**
182		* Takes many predicates and returns a new predicate that
183		* returns `true` if any of the predicates is satisfied.
184		*
185		* If no predicate is given as argument, this function
186		* will return an always non-passing predicate.
187		* ```php
188		* $startsOrEndsWith = function($text) {
189		* return F\any(F\startsWith($text), F\endsWith($text));
190		* };
191		* $test = $startsOrEndsWith('b');
192		* $test('bar'); //=> true
193		* $test('bob'); //=> true
194		* $test('foo'); //=> false
195		* $alwaysFlase = F\any();
196		* $alwaysFlase(1); //=> false
197		* $alwaysFlase(null); //=> false
198		* ```
199		*
200		* @signature ((a -> Boolean), ..., (a -> Boolean)) -> (a -> Boolean)
201		* @param callable $predicates...
		0 ignored issues – show Bug introduced 2016-12-21 00:21 UTC by Report Bug Copy Issue Report There is no parameter named `$predicates...`. Was it maybe removed? This check looks for PHPDoc comments describing methods or function parameters that do not exist on the corresponding method or function. Consider the following example. The parameter `$italy` is not defined by the method `finale(...)`. /** * @param array $germany * @param array $island * @param array $italy */ function finale($germany, $island) { return "2:1"; } The most likely cause is that the parameter was removed, but the annotation was not. Loading history...
202		* @return callable
203		*/
204	View Code Duplication	function any() {
		0 ignored issues – show Duplication introduced 2016-11-16 15:09 UTC by Report Bug Copy Issue Report This function seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
205		$predicates = func_get_args();
206		return function($value) use($predicates) {
207		return reduce(function($result, $predicate) use($value) {
208		return $result \|\| $predicate($value);
209		}, false, $predicates);
210		};
211		}
212
213		/**
214		* Takes a function `f` and returns a function `g` so that if `f` returns
215		* `x` for some arguments; `g` will return `! x` for the same arguments.
216		*
217		* Note that `complement($fn) == pipe($fn, not())`.
218		* ```php
219		* $isOdd = function($number) {
220		* return 1 == $number % 2;
221		* };
222		*
223		* $isEven = F\complement($isOdd);
224		*
225		* $isEven(5); //=> false
226		* $isEven(8); //=> true
227		* ```
228		*
229		* @signature (* -> ... -> ) -> ( -> ... -> Boolean)
230		* @param callable $fn
		0 ignored issues – show Bug introduced 2016-12-23 19:41 UTC by Report Bug Copy Issue Report There is no parameter named `$fn`. Was it maybe removed? This check looks for PHPDoc comments describing methods or function parameters that do not exist on the corresponding method or function. Consider the following example. The parameter `$italy` is not defined by the method `finale(...)`. /** * @param array $germany * @param array $island * @param array $italy */ function finale($germany, $island) { return "2:1"; } The most likely cause is that the parameter was removed, but the annotation was not. Loading history...
231		* @return callable
232		*/
233		function complement() {
234		static $complement = false;
235		$complement = $complement ?: curry(function($fn) {
236		return pipe($fn, not());
237		});
238		return _apply($complement, func_get_args());
239		}
240
241		/**
242		* Takes a function telling if the first argument is less then the second, and return a compare function.
243		*
244		* A compare function returns `-1`, `0`, or `1` if the first argument is considered
245		* to be respectively less than, equal to, or greater than the second.
246		* ```php
247		* $users = [
248		* ['name' => 'foo', 'age' => 21],
249		* ['name' => 'bar', 'age' => 11],
250		* ['name' => 'baz', 'age' => 15]
251		* ];
252		*
253		* usort($users, F\comparator(function($a, $b){
254		* return $a['age'] < $b['age'];
255		* }));
256		*
257		* F\map(F\get('name'), $users); //=> ['bar', 'baz', 'foo']
258		* ```
259		*
260		* @signature (a -> a -> Boolean) -> (a -> a -> Number)
261		* @param callable $fn
		0 ignored issues – show Bug introduced 2016-12-23 19:41 UTC by Report Bug Copy Issue Report There is no parameter named `$fn`. Was it maybe removed? This check looks for PHPDoc comments describing methods or function parameters that do not exist on the corresponding method or function. Consider the following example. The parameter `$italy` is not defined by the method `finale(...)`. /** * @param array $germany * @param array $island * @param array $italy */ function finale($germany, $island) { return "2:1"; } The most likely cause is that the parameter was removed, but the annotation was not. Loading history...
262		* @return callable
263		*/
264		function comparator() {
265		static $comparator = false;
266		$comparator = $comparator ?: curry(function($fn) {
267		return function($a, $b) use($fn) {
268		if ($fn($a, $b)) return -1;
269		if ($fn($b, $a)) return 1;
270		return 0;
271		};
272		});
273		return _apply($comparator, func_get_args());
274		}
275
276

tarsana / functional

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functions.php ➔ comparator() A

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