functions.php ➔ identity() - Code Metrics - Inspection of "added all() and any()" - tarsana/functional - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( 97f147...5a66ad )

by Amine

created 2016-11-16 15:07 UTC

functions.php ➔ identity() A

↳ Parent: Project

Complexity

Conditions	1
Paths	1

Size

Total Lines	5
Code Lines	4

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	1
eloc	4
nc	1
nop	0
dl	0
loc	5
rs	9.4285
c	0
b	0
f	0

<?php namespace Tarsana\Functional;
/**
 * This file contains functions dealing with functions.
 */

use Tarsana\Functional\Exceptions\InvalidArgument;

/**
 * Adds the `Tarsana\Functional\` namespace to a function name.
 * This is useful to pass non-curried functions as parameter.
 *
 * @internal
 * @signature String -> Sring
 * @param  string $name
 * @return string
 */
function _f($name) {
    return "Tarsana\\Functional\\{$name}";
}

/**
 * Gets the number of arguments of a function.
 *
 * @internal
 * @signature (* -> *) -> Number
 * @param  callable $fn
 * @return int
 */
function _number_of_args($fn) {
    $reflector = is_array($fn) ?
        new \ReflectionMethod($fn[0], $fn[1]) :
        new \ReflectionFunction($fn);
    return $reflector->getNumberOfRequiredParameters();
}

/**
 * Checks if `$a` is am argument placeholder.
 *
 * @internal
 * @signature * -> Boolean
 * @param  mixed  $a
 * @return boolean
 */
function _is_placeholder($a) {
    return $a instanceof Placeholder;
}

/**
 * Adds new given arguments to the list of bound arguments while filling placeholders.
 *
 * @internal
 * @signature Number -> [a] -> [a] -> [a]
 * @param  int   $fnArgsCount
 * @param  array $boundArgs
 * @param  array $givenArgs
 * @return array
 */
function _merge_args($fnArgsCount, $boundArgs, $givenArgs) {
    $addArgument = function($currentBoundArgs, $arg) use($fnArgsCount) {
        $currentBoundArgsCount = count($currentBoundArgs);
        $placeholderPosition = 0;
        while($placeholderPosition < $currentBoundArgsCount && !_is_placeholder($currentBoundArgs[$placeholderPosition]))
            $placeholderPosition ++;
        if ($currentBoundArgsCount < $fnArgsCount || $placeholderPosition == $currentBoundArgsCount) {
            $currentBoundArgs[] = $arg;
        } else { // There is a placeholder and number of bound args >= $fnArgsCount
            $currentBoundArgs[$placeholderPosition] = $arg;
        }
        return $currentBoundArgs;
    };

    return array_reduce($givenArgs, $addArgument, $boundArgs);
}

/**
 * Returns the curried version of a function with some arguments bound to it.
 *
 * @internal
 * @signature (* -> *) -> Number -> [*] -> (* -> *)
 * @param  callable $fn
 * @param  int $argsCount
 * @param  array  $boundArgs
 * @return callable
 */
function _curried_function($fn, $argsCount, $boundArgs = []) {
    return function() use($fn, $argsCount, $boundArgs) {
        $boundArgs = _merge_args($argsCount, $boundArgs, func_get_args());
$x = 1;
$callable = function() use ($x) {
    $x = 2; // Not visible in outer scope. If you would like this, how
            // about using a different variable name than $x?
};

$callable();
var_dump($x); // integer(1)
        $numberOfPlaceholders = count(array_filter($boundArgs, _f('_is_placeholder')));
        $numberOfGivenArgs = count($boundArgs) - $numberOfPlaceholders;
        if ($numberOfGivenArgs >= $argsCount)
            return call_user_func_array($fn, $boundArgs);
        return _curried_function($fn, $argsCount, $boundArgs);
    };
}

/**
 * Returns a curried equivalent of the provided function.
 * ```php
 * $add = curry(function($x, $y){
 *     return $x + $y;
 * });
 * $addFive = $add(5); // a function
 * $addFive(5); // 10
 * $add(5, 5) // 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
 * $minus = curry(function ($x, $y) { return $x - $y; });
 * $decrement = $minus(__(), 1);
 * $decrement(10) // 9
 *
 * $reduce = curry('array_reduce');
 * $sum = $reduce(__(), 'Tarsana\Functional\plus');
 * $sum([1, 2, 3, 4], 0) // 10
 * ```
 *
 * @signature * -> Placeholder
 * @return \Cypress\Curry\Placeholder
 */
function __() {
    return Placeholder::get();
}

/**
 * Non curried version of apply for internal use.
 *
 * @internal
 * @param  callable $fn
 * @param  array    $args
 * @return mixed
 */
function _apply($fn, $args) {
    return call_user_func_array($fn, $args);
}

/**
 * Apply the provided function to the list of arguments.
 * ```php
 * apply('strlen', ['Hello']) // 5
 * $replace = 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() {
    return _apply(curry(f('_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
 * function add($x, $y) { return $x + $y; }
 * $double = function($x) { return 2 * $x; };
 * $addThenDouble = pipe('add', $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)
        throw new InvalidArgument("pipe() requires at least one argument");
    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
 * identity('Hello') // 'Hello'
 * identity([1, 2, 3]) // [1, 2, 3]
 * identity(null) // null
 * ```
 *
 * @signature * -> *
 * @return mixed
 */
function identity() {
    return apply(curry(function($value) {
        return $value;
    }), func_get_args());
}

/**
 * Returns a function which whenever called will return the specified value.
 * ```php
 * $five = give(5);
 * $five(); // 5
 * $null = 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() {
    $give = function($value) {
        return function() use($value) {
            return $value;
        };
    };
    return apply(curry($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 = all(gte(__(), 1), lte(__(), 10));
 * $betweenOneAndTen(5); // true
 * $betweenOneAndTen(0); // false
 * $alwaysTrue = 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 passing predicate.
 * ```php
 * $startsOrEndsWith = function($text) {
 *     return any(startsWith($text), endsWth($text));
 * };
 * $test = $startsOrEndsWith('b');
 * $test('bar'); // true
 * $test('bob'); // true
 * $test('foo'); // false
 * $alwaysTrue = any();
 * $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 any() {

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



Push — master ( 97f147...5a66ad )

functions.php ➔ identity() A

Complexity

Size

Duplication

Importance

Change not visible in outer-scope

Change visible in outer-scope

1		<?php namespace Tarsana\Functional;
2		/**
3		* This file contains functions dealing with functions.
4		*/
5
6		use Tarsana\Functional\Exceptions\InvalidArgument;
7
8		/**
9		* Adds the `Tarsana\Functional\` namespace to a function name.
10		* This is useful to pass non-curried functions as parameter.
11		*
12		* @internal
13		* @signature String -> Sring
14		* @param string $name
15		* @return string
16		*/
17		function _f($name) {
18		return "Tarsana\\Functional\\{$name}";
19		}
20
21		/**
22		* Gets the number of arguments of a function.
23		*
24		* @internal
25		* @signature (* -> *) -> Number
26		* @param callable $fn
27		* @return int
28		*/
29		function _number_of_args($fn) {
30		$reflector = is_array($fn) ?
31		new \ReflectionMethod($fn[0], $fn[1]) :
32		new \ReflectionFunction($fn);
33		return $reflector->getNumberOfRequiredParameters();
34		}
35
36		/**
37		* Checks if `$a` is am argument placeholder.
38		*
39		* @internal
40		* @signature * -> Boolean
41		* @param mixed $a
42		* @return boolean
43		*/
44		function _is_placeholder($a) {
45		return $a instanceof Placeholder;
46		}
47
48		/**
49		* Adds new given arguments to the list of bound arguments while filling placeholders.
50		*
51		* @internal
52		* @signature Number -> [a] -> [a] -> [a]
53		* @param int $fnArgsCount
54		* @param array $boundArgs
55		* @param array $givenArgs
56		* @return array
57		*/
58		function _merge_args($fnArgsCount, $boundArgs, $givenArgs) {
59		$addArgument = function($currentBoundArgs, $arg) use($fnArgsCount) {
60		$currentBoundArgsCount = count($currentBoundArgs);
61		$placeholderPosition = 0;
62		while($placeholderPosition < $currentBoundArgsCount && !_is_placeholder($currentBoundArgs[$placeholderPosition]))
63		$placeholderPosition ++;
64		if ($currentBoundArgsCount < $fnArgsCount \|\| $placeholderPosition == $currentBoundArgsCount) {
65		$currentBoundArgs[] = $arg;
66		} else { // There is a placeholder and number of bound args >= $fnArgsCount
67		$currentBoundArgs[$placeholderPosition] = $arg;
68		}
69		return $currentBoundArgs;
70		};
71
72		return array_reduce($givenArgs, $addArgument, $boundArgs);
73		}
74
75		/**
76		* Returns the curried version of a function with some arguments bound to it.
77		*
78		* @internal
79		* @signature (* -> ) -> Number -> [] -> (* -> *)
80		* @param callable $fn
81		* @param int $argsCount
82		* @param array $boundArgs
83		* @return callable
84		*/
85		function _curried_function($fn, $argsCount, $boundArgs = []) {
86		return function() use($fn, $argsCount, $boundArgs) {
87		$boundArgs = _merge_args($argsCount, $boundArgs, func_get_args());
		0 ignored issues – show Bug introduced 2016-11-14 23:35 UTC by Report Bug Copy Issue Report Consider using a different name than the imported variable `$boundArgs`, or did you forget to import by reference? It seems like you are assigning to a variable which was imported through a `use` statement which was not imported by reference. For clarity, we suggest to use a different name or import by reference depending on whether you would like to have the change visibile in outer-scope. Change not visible in outer-scope $x = 1; $callable = function() use ($x) { $x = 2; // Not visible in outer scope. If you would like this, how // about using a different variable name than $x? }; $callable(); var_dump($x); // integer(1) Change visible in outer-scope $x = 1; $callable = function() use (&$x) { $x = 2; }; $callable(); var_dump($x); // integer(2) Loading history...
88		$numberOfPlaceholders = count(array_filter($boundArgs, _f('_is_placeholder')));
89		$numberOfGivenArgs = count($boundArgs) - $numberOfPlaceholders;
90		if ($numberOfGivenArgs >= $argsCount)
91		return call_user_func_array($fn, $boundArgs);
92		return _curried_function($fn, $argsCount, $boundArgs);
93		};
94		}
95
96		/**
97		* Returns a curried equivalent of the provided function.
98		* ```php
99		* $add = curry(function($x, $y){
100		* return $x + $y;
101		* });
102		* $addFive = $add(5); // a function
103		* $addFive(5); // 10
104		* $add(5, 5) // 10
105		* ```
106		*
107		* @signature (* -> a) -> (* -> a)
108		* @param callable $fn
109		* @return callable
110		*/
111		function curry($fn) {
112		return _curried_function($fn, _number_of_args($fn));
113		}
114
115		/**
116		* Argument placeholder to use with curried functions.
117		* ```php
118		* $minus = curry(function ($x, $y) { return $x - $y; });
119		* $decrement = $minus(__(), 1);
120		* $decrement(10) // 9
121		*
122		* $reduce = curry('array_reduce');
123		* $sum = $reduce(__(), 'Tarsana\Functional\plus');
124		* $sum([1, 2, 3, 4], 0) // 10
125		* ```
126		*
127		* @signature * -> Placeholder
128		* @return \Cypress\Curry\Placeholder
129		*/
130		function __() {
131		return Placeholder::get();
132		}
133
134		/**
135		* Non curried version of apply for internal use.
136		*
137		* @internal
138		* @param callable $fn
139		* @param array $args
140		* @return mixed
141		*/
142		function _apply($fn, $args) {
143		return call_user_func_array($fn, $args);
144		}
145
146		/**
147		* Apply the provided function to the list of arguments.
148		* ```php
149		* apply('strlen', ['Hello']) // 5
150		* $replace = apply('str_replace');
151		* $replace(['l', 'o', 'Hello']) // 'Heooo'
152		* ```
153		*
154		* @signature (... -> a) -> [] -> a
155		* @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...
156		* @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, $island) { return "2:1"; } The most likely cause is that the parameter was removed, but the annotation was not. Loading history...
157		* @return mixed
158		*/
159		function apply() {
160		return _apply(curry(f('_apply')), func_get_args());
161		}
162
163		/**
164		* Performs left-to-right function composition.
165		* The leftmost function may have any arity;
166		* the remaining functions must be unary.
167		* The result of pipe is curried.
168		* Calling pipe() without any argument returns the `identity` function
169		* ```php
170		* function add($x, $y) { return $x + $y; }
171		* $double = function($x) { return 2 * $x; };
172		* $addThenDouble = pipe('add', $double);
173		* $addThenDouble(2, 3) // 10
174		* ```
175		*
176		* @signature (((a, b, ...) -> o), (o -> p), ..., (y -> z)) -> ((a, b, ...) -> z)
177		* @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...
178		* @return callable
179		*/
180		function pipe() {
181		$fns = func_get_args();
182		if(count($fns) < 1)
183		throw new InvalidArgument("pipe() requires at least one argument");
184		return curry(function () use ($fns) {
185		$result = _apply(array_shift($fns), func_get_args());
186		foreach ($fns as $fn) {
187		$result = $fn($result);
188		}
189		return $result;
190		});
191		}
192
193		/**
194		* A function that takes one argument and
195		* returns exactly the given argument.
196		* ```php
197		* identity('Hello') // 'Hello'
198		* identity([1, 2, 3]) // [1, 2, 3]
199		* identity(null) // null
200		* ```
201		*
202		* @signature * -> *
203		* @return mixed
204		*/
205		function identity() {
206		return apply(curry(function($value) {
207		return $value;
208		}), func_get_args());
209		}
210
211		/**
212		* Returns a function which whenever called will return the specified value.
213		* ```php
214		* $five = give(5);
215		* $five(); // 5
216		* $null = give(null);
217		* $null(); // null
218		* ```
219		*
220		* @signature a -> (* -> a)
221		* @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...
222		* @return callable
223		*/
224		function give() {
225		$give = function($value) {
226		return function() use($value) {
227		return $value;
228		};
229		};
230		return apply(curry($give), func_get_args());
231		}
232
233		/**
234		* Takes many predicates and returns a new predicate that
235		* returns `true` only if all predicates are satisfied.
236		* If no predicate is given as argument, this function
237		* will return an always passing predicate.
238		* ```php
239		* $betweenOneAndTen = all(gte(__(), 1), lte(__(), 10));
240		* $betweenOneAndTen(5); // true
241		* $betweenOneAndTen(0); // false
242		* $alwaysTrue = all();
243		* $alwaysTrue(1); // true
244		* $alwaysTrue(null); // true
245		* ```
246		*
247		* @signature ((a -> Boolean), ..., (a -> Boolean)) -> (a -> Boolean)
248		* @param callable $predicates...
		0 ignored issues – show Bug introduced 2016-11-16 15:09 UTC by Report Bug Copy Issue Report There is no parameter named `$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...
249		* @return callable
250		*/
251	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...
252		$predicates = func_get_args();
253		return function($value) use($predicates) {
254		return reduce(function($result, $predicate) use($value) {
255		return $result && $predicate($value);
256		}, true, $predicates);
257		};
258		}
259
260		/**
261		* Takes many predicates and returns a new predicate that
262		* returns `true` if any of the predicates is satisfied.
263		* If no predicate is given as argument, this function
264		* will return an always passing predicate.
265		* ```php
266		* $startsOrEndsWith = function($text) {
267		* return any(startsWith($text), endsWth($text));
268		* };
269		* $test = $startsOrEndsWith('b');
270		* $test('bar'); // true
271		* $test('bob'); // true
272		* $test('foo'); // false
273		* $alwaysTrue = any();
274		* $alwaysTrue(1); // true
275		* $alwaysTrue(null); // true
276		* ```
277		*
278		* @signature ((a -> Boolean), ..., (a -> Boolean)) -> (a -> Boolean)
279		* @param callable $predicates...
		0 ignored issues – show Bug introduced 2016-11-16 15:09 UTC by Report Bug Copy Issue Report There is no parameter named `$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...
280		* @return callable
281		*/
282	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...
283		$predicates = func_get_args();
284		return function($value) use($predicates) {
285		return reduce(function($result, $predicate) use($value) {
286		return $result \|\| $predicate($value);
287		}, true, $predicates);
288		};
289		}
290
291

tarsana / functional

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functions.php ➔ identity() A

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