_functions.php ➔ _apply()   B
last analyzed

Complexity

Conditions 7
Paths 7

Size

Total Lines 11

Duplication

Lines 2
Ratio 18.18 %

Importance

Changes 0
Metric Value
cc 7
nc 7
nop 2
dl 2
loc 11
rs 8.8333
c 0
b 0
f 0
1
<?php namespace Tarsana\Functional;
2
/**
3
 * This file contains common internal functions.
4
 * Caution: Code written here may seems stupid because it
5
 * contains a lot of duplications and low level optimisation,
6
 * but this is needed to make the library as efficient as possible.
7
 * @file
8
 */
9
10
/**
11
 * Adds the `Tarsana\Functional` namespace to a function name.
12
 * This is useful to pass non-curried functions as parameter.
13
 * ```php
14
 * F\_f('foo'); //=> 'Tarsana\Functional\foo'
15
 * ```
16
 *
17
 * @signature String -> Sring
18
 * @param  string $name
19
 * @return string
20
 */
21
function _f($name) {
22
    $name = "Tarsana\\Functional\\{$name}";
23
    return $name;
24
}
25
26
/**
27
 * Gets the number of arguments of a function.
28
 * ```php
29
 * F\_number_of_args(function($x, $y){}); //=> 2
30
 * ```
31
 *
32
 * @signature (* -> *) -> Number
33
 * @param  callable $fn
34
 * @return int
35
 */
36
function _number_of_args($fn) {
37
    $reflector = is_array($fn) ?
38
        new \ReflectionMethod($fn[0], $fn[1]) :
39
        new \ReflectionFunction($fn);
40
    return $reflector->getNumberOfRequiredParameters();
41
}
42
43
/**
44
 * Non curried version of apply for internal use.
45
 *
46
 * ```php
47
 * $sum = function() {
48
 *     return F\sum(func_get_args());
49
 * };
50
 * F\_apply($sum, [1, 2, 3, 4, 5]); //=> 15
51
 * F\_apply($sum, [1, 2, 3, 4, 5, 6]); //=> 21
52
 * ```
53
 *
54
 * @param  callable $fn
55
 * @param  array    $args
56
 * @return mixed
57
 */
58
function _apply($fn, $args) {
59
    switch (count($args)) {
60
        case 0: return $fn();
0 ignored issues
show
Coding Style introduced by
The case body in a switch statement must start on the line following the statement.

According to the PSR-2, the body of a case statement must start on the line immediately following the case statement.

switch ($expr) {
case "A":
    doSomething(); //right
    break;
case "B":

    doSomethingElse(); //wrong
    break;

}

To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.

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Coding Style introduced by
Terminating statement must be on a line by itself

As per the PSR-2 coding standard, the break (or other terminating) statement must be on a line of its own.

switch ($expr) {
     case "A":
         doSomething();
         break; //wrong
     case "B":
         doSomething();
         break; //right
     case "C:":
         doSomething();
         return true; //right
 }

To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.

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61
        case 1: return $fn($args[0]);
0 ignored issues
show
Coding Style introduced by
The case body in a switch statement must start on the line following the statement.

According to the PSR-2, the body of a case statement must start on the line immediately following the case statement.

switch ($expr) {
case "A":
    doSomething(); //right
    break;
case "B":

    doSomethingElse(); //wrong
    break;

}

To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.

Loading history...
Coding Style introduced by
Terminating statement must be on a line by itself

As per the PSR-2 coding standard, the break (or other terminating) statement must be on a line of its own.

switch ($expr) {
     case "A":
         doSomething();
         break; //wrong
     case "B":
         doSomething();
         break; //right
     case "C:":
         doSomething();
         return true; //right
 }

To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.

Loading history...
62
        case 2: return $fn($args[0], $args[1]);
0 ignored issues
show
Coding Style introduced by
The case body in a switch statement must start on the line following the statement.

According to the PSR-2, the body of a case statement must start on the line immediately following the case statement.

switch ($expr) {
case "A":
    doSomething(); //right
    break;
case "B":

    doSomethingElse(); //wrong
    break;

}

To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.

Loading history...
Coding Style introduced by
Terminating statement must be on a line by itself

As per the PSR-2 coding standard, the break (or other terminating) statement must be on a line of its own.

switch ($expr) {
     case "A":
         doSomething();
         break; //wrong
     case "B":
         doSomething();
         break; //right
     case "C:":
         doSomething();
         return true; //right
 }

To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.

Loading history...
63
        case 3: return $fn($args[0], $args[1], $args[2]);
0 ignored issues
show
Coding Style introduced by
The case body in a switch statement must start on the line following the statement.

According to the PSR-2, the body of a case statement must start on the line immediately following the case statement.

switch ($expr) {
case "A":
    doSomething(); //right
    break;
case "B":

    doSomethingElse(); //wrong
    break;

}

To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.

Loading history...
Coding Style introduced by
Terminating statement must be on a line by itself

As per the PSR-2 coding standard, the break (or other terminating) statement must be on a line of its own.

switch ($expr) {
     case "A":
         doSomething();
         break; //wrong
     case "B":
         doSomething();
         break; //right
     case "C:":
         doSomething();
         return true; //right
 }

To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.

Loading history...
64 View Code Duplication
        case 4: return $fn($args[0], $args[1], $args[2], $args[3]);
0 ignored issues
show
Duplication introduced by
This code seems to be duplicated across 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...
Coding Style introduced by
The case body in a switch statement must start on the line following the statement.

According to the PSR-2, the body of a case statement must start on the line immediately following the case statement.

switch ($expr) {
case "A":
    doSomething(); //right
    break;
case "B":

    doSomethingElse(); //wrong
    break;

}

To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.

Loading history...
Coding Style introduced by
Terminating statement must be on a line by itself

As per the PSR-2 coding standard, the break (or other terminating) statement must be on a line of its own.

switch ($expr) {
     case "A":
         doSomething();
         break; //wrong
     case "B":
         doSomething();
         break; //right
     case "C:":
         doSomething();
         return true; //right
 }

To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.

Loading history...
65 View Code Duplication
        case 5: return $fn($args[0], $args[1], $args[2], $args[3], $args[4]);
0 ignored issues
show
Duplication introduced by
This code seems to be duplicated across 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...
Coding Style introduced by
The case body in a switch statement must start on the line following the statement.

According to the PSR-2, the body of a case statement must start on the line immediately following the case statement.

switch ($expr) {
case "A":
    doSomething(); //right
    break;
case "B":

    doSomethingElse(); //wrong
    break;

}

To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.

Loading history...
Coding Style introduced by
Terminating statement must be on a line by itself

As per the PSR-2 coding standard, the break (or other terminating) statement must be on a line of its own.

switch ($expr) {
     case "A":
         doSomething();
         break; //wrong
     case "B":
         doSomething();
         break; //right
     case "C:":
         doSomething();
         return true; //right
 }

To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.

Loading history...
66
    }
67
    return call_user_func_array($fn, $args);
68
}
69
70
/**
71
 * Checks if `$a` is an argument placeholder.
72
 * ```php
73
 * F\_is_placeholder(F\__()); //=> true
74
 * F\_is_placeholder('other thing'); //=> false
75
 * ```
76
 *
77
 * @signature * -> Boolean
78
 * @param  mixed  $a
79
 * @return boolean
80
 */
81
function _is_placeholder($a) {
82
    return $a instanceof Placeholder;
83
}
84
85
/**
86
 * Curry an unary function.
87
 *
88
 * @ignore
89
 * @signature (a -> b) -> (a -> b)
90
 * @param  callable $fn
91
 * @return callable
92
 */
93
function _curry_one($fn) {
94
    return function() use($fn) {
95
        $args = func_get_args();
96
        return (count($args) > 0 && ! _is_placeholder($args[0]))
97
            ? $fn($args[0])
98
            : _curry_one($fn);
99
    };
100
}
101
102
/**
103
 * Curry an binary function.
104
 *
105
 * ```php
106
 * $add = F\_curry_two(function($x, $y) {
107
 *     return $x + $y;
108
 * });
109
 *
110
 * $addOne = $add(1, F\__());
111
 * $addOne(2); //=> 3
112
 * ```
113
 *
114
 * @signature (a,b -> c) -> (a -> b -> c)
115
 * @param  callable $fn
116
 * @return callable
117
 */
118
function _curry_two($fn) {
119
    return function() use($fn) {
120
        $args = func_get_args();
121
        $n = count($args);
122
        while ($n > 0 && _is_placeholder($args[$n - 1]))
123
            $n --;
124
        if ($n == 0)
125
            return _curry_two($fn);
126
        if ($n == 1) {
127
            $a = &$args[0];
128
            if (_is_placeholder($a))
129
                return _curry_two($fn);
130
            return _curry_one(function($b) use($fn, &$a) {
131
                return $fn($a, $b);
132
            });
133
        }
134
        $a = &$args[0];
135
        $b = &$args[1];
136
        if (_is_placeholder($a) && _is_placeholder($b))
137
            return _curry_two($fn);
138
        if (_is_placeholder($a))
139
            return _curry_one(function($_a) use($fn, &$b) {
140
                return $fn($_a, $b);
141
            });
142
        return $fn($args[0], $args[1]);
143
    };
144
}
145
146
/**
147
 * Curry a function with 3 arguments.
148
 *
149
 * ```php
150
 * $add = F\_curry_three(function($x, $y, $z) {
151
 *     return $x + $y + $z;
152
 * });
153
 *
154
 * $add(1, 2, 3); //=> 6
155
 * $f = $add(F\__(), 2, F\__());
156
 * $f(1, 3); //=> 6
157
 * $g = $add(1, F\__(), 3);
158
 * $g(2); //=> 6
159
 * $h = $add(F\__(), F\__(), 3);
160
 * $h(1, 2); //=> 6
161
 * $i = $add(F\__(), 2, 3);
162
 * $i(1); //=> 6
163
 * ```
164
 *
165
 * @signature (a,b,c -> d) -> (a -> b -> c -> d)
166
 * @param  callable $fn
167
 * @return callable
168
 */
169
function _curry_three($fn) {
170
    return function() use($fn) {
171
        $args = func_get_args();
172
        $n = count($args);
173
        while ($n > 0 && _is_placeholder($args[$n - 1]))
174
            $n --;
175
        if ($n == 0)
176
            return _curry_three($fn);
177
        if ($n == 1) {
178
            $a = &$args[0];
179
            return _curry_two(function($b, $c) use($fn, &$a) {
180
                return $fn($a, $b, $c);
181
            });
182
        }
183
        if ($n == 2) {
184
            $a = &$args[0]; $b = &$args[1];
185
186
            if (_is_placeholder($a))
187
                return _curry_two(function($_a, $c) use($fn, &$b) {
188
                    return $fn($_a, $b, $c);
189
                });
190
            return _curry_one(function($c) use($fn, &$a, &$b) {
191
                return $fn($a, $b, $c);
192
            });
193
        }
194
195
        $a = &$args[0]; $b = &$args[1]; $c = &$args[2];
196
197 View Code Duplication
        if (_is_placeholder($a) && _is_placeholder($b))
0 ignored issues
show
Duplication introduced by
This code seems to be duplicated across 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.

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198
            return _curry_two(function($_a, $_b) use($fn, &$c) {
199
                return $fn($_a, $_b, $c);
200
            });
201 View Code Duplication
        if (_is_placeholder($a))
0 ignored issues
show
Duplication introduced by
This code seems to be duplicated across 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...
202
            return _curry_one(function($_a) use($fn, &$b, &$c) {
203
                return $fn($_a, $b, $c);
204
            });
205 View Code Duplication
        if (_is_placeholder($b))
0 ignored issues
show
Duplication introduced by
This code seems to be duplicated across 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...
206
            return _curry_one(function($_b) use($fn, &$a, &$c) {
207
                return $fn($a, $_b, $c);
208
            });
209
210
        return $fn($a, $b, $c);
211
    };
212
}
213
214
/**
215
 * Curry a function with `$n` arguments.
216
 *
217
 * ```php
218
 * $polynomial = F\_curry_n(function($a, $b, $c, $x) {
219
 *     return $a * $x * $x + $b * $x + $c;
220
 * }, 4);
221
 *
222
 * $linear = $polynomial(0);
223
 * $linear(2, 1, 5); //=> 11
224
 * ```
225
 *
226
 * @signature (*... -> *) -> Number -> (* -> ... -> *)
227
 * @param  callable $fn
228
 * @param  int $n
229
 * @param  array $given
230
 * @return callable
231
 */
232
function _curry_n($fn, $n, $given = []) {
233
    return function() use($fn, $n, $given) {
234
        $args = func_get_args();
235
        $merged = _merge_args($given, $args, $n);
236
        $args = $merged->args;
237
        switch ($merged->placeholders) {
238
            case 0: return _apply($fn, $args);
0 ignored issues
show
Coding Style introduced by
The case body in a switch statement must start on the line following the statement.

According to the PSR-2, the body of a case statement must start on the line immediately following the case statement.

switch ($expr) {
case "A":
    doSomething(); //right
    break;
case "B":

    doSomethingElse(); //wrong
    break;

}

To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.

Loading history...
Coding Style introduced by
Terminating statement must be on a line by itself

As per the PSR-2 coding standard, the break (or other terminating) statement must be on a line of its own.

switch ($expr) {
     case "A":
         doSomething();
         break; //wrong
     case "B":
         doSomething();
         break; //right
     case "C:":
         doSomething();
         return true; //right
 }

To learn more about the PSR-2 coding standard, please refer to the PHP-Fig.

Loading history...
239
            case 1:
240
                return _curry_one(function($a) use($fn, &$args) {
241
                    return _apply($fn, _fill_placeholders($args, [$a]));
242
                });
243
            case 2:
244
                return _curry_two(function($a, $b) use($fn, &$args) {
245
                    return _apply($fn, _fill_placeholders($args, [$a, $b]));
246
                });
247
            case 3:
248
                return _curry_three(function($a, $b, $c) use($fn, &$args) {
249
                    return _apply($fn, _fill_placeholders($args, [$a, $b, $c]));
250
                });
251
        }
252
        return _curry_n($fn, $n, $args);
253
    };
254
}
255
256
/**
257
 * Merges already given with new arguments, filling placeholders in the process.
258
 * Returns an object holding the resulting args and the number of placeholders left.
259
 *
260
 * ```php
261
 * $given = [F\__(), 2];
262
 * $args = [1, 3];
263
 * $newArgs = F\_merge_args($given, $args, 4);
264
 * $newArgs; //=> (object) ['args' => [1, 2, 3, F\__()], 'placeholders' => 1]
265
 * ```
266
 *
267
 * @param  array &$given
268
 * @param  array &$args
269
 * @param  int $n
270
 * @return object
271
 */
272
function _merge_args(&$given, &$args, $n) {
273
    $merged = (object) [
274
        'args' => [],
275
        'placeholders' => 0
276
    ];
277
    $givenIndex = 0; $argsIndex = 0; $mergedIndex = 0;
278
    $givenCount = count($given); $argsCount = count($args);
279
    while ($mergedIndex < $n && ($givenIndex < $givenCount || $argsIndex < $argsCount)) {
280
        if ($givenIndex < $givenCount && !_is_placeholder($given[$givenIndex])) {
281
            $merged->args[$mergedIndex] = $given[$givenIndex];
282
        } else if ($argsIndex < $argsCount) {
283
            $merged->args[$mergedIndex] = $args[$argsIndex];
284
            $argsIndex ++;
285
        } else {
286
            $merged->args[$mergedIndex] = $given[$givenIndex];
287
        }
288
289
        if (_is_placeholder($merged->args[$mergedIndex]))
290
            $merged->placeholders ++;
291
292
        $givenIndex ++;
293
        $mergedIndex ++;
294
    }
295
    while ($mergedIndex < $n) {
296
        $merged->args[$mergedIndex] = Placeholder::get();
297
        $mergedIndex ++;
298
        $merged->placeholders ++;
299
    }
300
    return $merged;
301
}
302
303
function _fill_placeholders($args, $fillers) {
304
    $argsIndex = 0; $fillersIndex = 0;
305
    $argsCount = count($args);
0 ignored issues
show
Unused Code introduced by
$argsCount is not used, you could remove the assignment.

This check looks for variable assignements that are either overwritten by other assignments or where the variable is not used subsequently.

$myVar = 'Value';
$higher = false;

if (rand(1, 6) > 3) {
    $higher = true;
} else {
    $higher = false;
}

Both the $myVar assignment in line 1 and the $higher assignment in line 2 are dead. The first because $myVar is never used and the second because $higher is always overwritten for every possible time line.

Loading history...
306
    $fillersCount = count($fillers);
307
    while ($fillersIndex < $fillersCount) {
308
        while (!_is_placeholder($args[$argsIndex]))
309
            $argsIndex ++;
310
        $args[$argsIndex] = $fillers[$fillersIndex];
311
        $fillersIndex ++;
312
    }
313
    return $args;
314
}
315