Completed
Pull Request — master (#3)
by Amine
02:42
created

_functions.php ➔ _fill_placeholders()   A

Complexity

Conditions 3
Paths 3

Size

Total Lines 12
Code Lines 10

Duplication

Lines 0
Ratio 0 %

Importance

Changes 0
Metric Value
cc 3
eloc 10
nc 3
nop 2
dl 0
loc 12
rs 9.4285
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
 * @param  callable $fn
47
 * @param  array    $args
48
 * @return mixed
49
 */
50
function _apply($fn, $args) {
51
    switch (count($args)) {
52
        case 0: return $fn();
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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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53
        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...
54
        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...
55
        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...
56 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...
57 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...
58
    }
59
    return call_user_func_array($fn, $args);
60
}
61
62
/**
63
 * Checks if `$a` is an argument placeholder.
64
 * ```php
65
 * F\_is_placeholder(F\__()); //=> true
66
 * F\_is_placeholder('other thing'); //=> false
67
 * ```
68
 *
69
 * @signature * -> Boolean
70
 * @param  mixed  $a
71
 * @return boolean
72
 */
73
function _is_placeholder($a) {
74
    return $a instanceof Placeholder;
75
}
76
77
/**
78
 * Curry an unary function.
79
 *
80
 * @ignore
81
 * @signature (a -> b) -> (a -> b)
82
 * @param  callable $fn
83
 * @return callable
84
 */
85
function _curry_one($fn) {
86
    return function() use($fn) {
87
        $args = func_get_args();
88
        return (count($args) > 0 && ! _is_placeholder($args[0]))
89
            ? $fn($args[0])
90
            : _curry_one($fn);
91
    };
92
}
93
94
/**
95
 * Curry an binary function.
96
 *
97
 * @ignore
98
 * @signature (a,b -> c) -> (a -> b -> c)
99
 * @param  callable $fn
100
 * @return callable
101
 */
102
function _curry_two($fn) {
103
    return function() use($fn) {
104
        $args = func_get_args();
105
        $n = count($args);
106
        if ($n == 0)
107
            return _curry_two($fn);
108
        if ($n == 1) {
109
            $a = &$args[0];
110
            if (_is_placeholder($a))
111
                return _curry_two($fn);
112
            return _curry_one(function($b) use($fn, &$a) {
113
                return $fn($a, $b);
114
            });
115
        }
116
        $a = &$args[0];
117
        $b = &$args[1];
118
        if (_is_placeholder($a) && _is_placeholder($b))
119
            return _curry_two($fn);
120
        if (_is_placeholder($a))
121
            return _curry_one(function($_a) use($fn, &$b) {
122
                return $fn($_a, $b);
123
            });
124
        if (_is_placeholder($b))
125
            return _curry_one(function($_b) use($fn, &$a) {
126
                return $fn($a, $_b);
127
            });
128
        return $fn($args[0], $args[1]);
129
    };
130
}
131
132
/**
133
 * Curry a function with 3 arguments.
134
 *
135
 * @ignore
136
 * @signature (a,b,c -> d) -> (a -> b -> c -> d)
137
 * @param  callable $fn
138
 * @return callable
139
 */
140
function _curry_three($fn) {
141
    return function() use($fn) {
142
        $args = func_get_args();
143
        $n = count($args);
144
        while ($n > 0 && _is_placeholder($args[$n - 1]))
145
            $n --;
146
        if ($n == 0)
147
            return _curry_three($fn);
148
        if ($n == 1) {
149
            $a = &$args[0];
150
            return _curry_two(function($b, $c) use($fn, &$a) {
151
                return $fn($a, $b, $c);
152
            });
153
        }
154
        if ($n == 2) {
155
            $a = &$args[0]; $b = &$args[1];
156
157
            if (_is_placeholder($a))
158
                return _curry_one(function($_a, $c) use(&$b) {
159
                    return $fn($_a, $b, $c);
0 ignored issues
show
Bug introduced by
The variable $fn does not exist. Did you forget to declare it?

This check marks access to variables or properties that have not been declared yet. While PHP has no explicit notion of declaring a variable, accessing it before a value is assigned to it is most likely a bug.

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160
                });
161
            return _curry_one(function($c) use($fn, &$a, &$b) {
162
                return $fn($a, $b, $c);
163
            });
164
        }
165
166
        $a = &$args[0]; $b = &$args[1]; $c = &$args[2];
167
168 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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169
            return _cuury_two(function($_a, $_b) use(&$c) {
170
                return $fn($_a, $_b, $c);
0 ignored issues
show
Bug introduced by
The variable $fn does not exist. Did you forget to declare it?

This check marks access to variables or properties that have not been declared yet. While PHP has no explicit notion of declaring a variable, accessing it before a value is assigned to it is most likely a bug.

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171
            });
172 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...
173
            return _cuury_one(function($_a) use(&$b, &$c) {
174
                return $fn($_a, $b, $c);
0 ignored issues
show
Bug introduced by
The variable $fn does not exist. Did you forget to declare it?

This check marks access to variables or properties that have not been declared yet. While PHP has no explicit notion of declaring a variable, accessing it before a value is assigned to it is most likely a bug.

Loading history...
175
            });
176 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...
177
            return _cuury_one(function($_b) use(&$a, &$c) {
178
                return $fn($a, $_b, $c);
0 ignored issues
show
Bug introduced by
The variable $fn does not exist. Did you forget to declare it?

This check marks access to variables or properties that have not been declared yet. While PHP has no explicit notion of declaring a variable, accessing it before a value is assigned to it is most likely a bug.

Loading history...
179
            });
180
181
        return $fn($a, $b, $c);
182
    };
183
}
184
185
/**
186
 * Curry a function with `$n` arguments.
187
 *
188
 * @ignore
189
 * @signature (*... -> *) -> Number -> (* -> ... -> *)
190
 * @param  callable $fn
191
 * @param  int $n
192
 * @param  array $given
193
 * @return callable
194
 */
195
function _curry_n($fn, $n, $given = []) {
196
    return function() use($fn, $n, $given) {
197
        $args = func_get_args();
198
        $merged = _merge_args($given, $args, $n);
199
        $args = $merged->args;
200
        switch ($merged->placeholders) {
201
            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...
202
            case 1:
203
                return _curry_one(function($a) use($fn, &$args) {
204
                    return _apply($fn, _fill_placeholders($args, [$a]));
205
                });
206
            case 2:
207
                return _curry_two(function($a, $b) use($fn, &$args) {
208
                    return _apply($fn, _fill_placeholders($args, [$a, $b]));
209
                });
210
            case 3:
211
                return _curry_three(function($a, $b, $c) use($fn, &$args) {
212
                    return _apply($fn, _fill_placeholders($args, [$a, $b, $c]));
213
                });
214
        }
215
        return _curry_n($fn, $n, $args);
216
    };
217
}
218
219
function _merge_args(&$given, &$args, $n) {
220
    $merged = (object) [
221
        'args' => [],
222
        'placeholders' => 0
223
    ];
224
    $givenIndex = 0; $argsIndex = 0; $mergedIndex = 0;
225
    $givenCount = count($given); $argsCount = count($args);
226
    while ($mergedIndex < $n && ($givenIndex < $givenCount || $argsIndex < $argsCount)) {
227
        if ($givenIndex < $givenCount && !_is_placeholder($given[$givenIndex])) {
228
            $merged->args[$mergedIndex] = $given[$givenIndex];
229
        } else if ($argsIndex < $argsCount) {
230
            $merged->args[$mergedIndex] = $args[$argsIndex];
231
            $argsIndex ++;
232
        } else {
233
            $merged->args[$mergedIndex] = $given[$givenIndex];
234
        }
235
236
        if (_is_placeholder($merged->args[$mergedIndex]))
237
            $merged->placeholders ++;
238
239
        $givenIndex ++;
240
        $mergedIndex ++;
241
    }
242
    while ($mergedIndex < $n) {
243
        $merged->args[$mergedIndex] = Placeholder::get();
244
        $mergedIndex ++;
245
        $merged->placeholders ++;
246
    }
247
    return $merged;
248
}
249
250
function _fill_placeholders($args, $fillers) {
251
    $argsIndex = 0; $fillersIndex = 0;
252
    $argsCount = count($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...
253
    $fillersCount = count($fillers);
254
    while ($fillersIndex < $fillersCount) {
255
        while (!_is_placeholder($args[$argsIndex]))
256
            $argsIndex ++;
257
        $args[$argsIndex] = $fillers[$fillersIndex];
258
        $fillersIndex ++;
259
    }
260
    return $args;
261
}
262