Online PHP editor | output for fmS6q

@ 2014-10-28T17:18:30Z

<?php

function chain($iterable, array $functions)
{
    foreach ($functions as $function) {
        $iterable = $function(as_iterator($iterable));
    }
    return $iterable;
}

function as_iterator($iterable)
{
    if ($iterable instanceof \Iterator) {
        return $iterable;
    }
    if (is_array($iterable)) {
        return new \ArrayIterator($iterable);
    }
    if (is_string($iterable)) {
        return new \ArrayIterator(str_split($iterable));
    }
    throw new \Exception();
}

function do_map(callable $function)
{
    return function(Iterator $iterator) use ($function) {
        foreach ($iterator as $key => $value) {
            yield $key => $function($value, $key);
        }
    };
}

function do_filter(callable $function)
{
    return function(Iterator $iterator) use($function) {
        foreach ($iterator as $key => $value) {
            if ($function($value, $key)) {
                yield $key => $value;
            }
        }
    };
}

function do_concat($iterable)
{
    return function(Iterator $iterator) use ($iterable) {
        foreach ($iterator as $value) {
            yield $value;
        }
        foreach (as_iterator($iterable) as $value) {
            yield $value;
        }
    };
}

function do_as_array()
{
    return function(Iterator $iterator) {
        return iterator_to_array($iterator);
    };
}

$array = chain([1, 2, 3, 4], [
    do_concat([5, 6, 7, 8]),
    do_filter(function ($v) { return $v % 2 == 0; }),
    do_map(function ($v) { return $v * 3; }),
    do_as_array(),
]);
var_dump($array);

Output for 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6: array(4) { [1]=> int(6) [3]=> int(12) [5]=> int(18) [7]=> int(24) }
Output for 5.4.0 - 5.4.45: Parse error: syntax error, unexpected '$key' (T_VARIABLE) in /in/fmS6q on line 29
Process exited with code 255.
Output for 5.3.0 - 5.3.29: Parse error: syntax error, unexpected T_VARIABLE in /in/fmS6q on line 29
Process exited with code 255.
Output for 5.1.0 - 5.1.6, 5.2.0 - 5.2.17: Warning: Unexpected character in input: '\' (ASCII=92) state=1 in /in/fmS6q on line 13 Warning: Unexpected character in input: '\' (ASCII=92) state=1 in /in/fmS6q on line 17 Warning: Unexpected character in input: '\' (ASCII=92) state=1 in /in/fmS6q on line 20 Warning: Unexpected character in input: '\' (ASCII=92) state=1 in /in/fmS6q on line 22 Parse error: syntax error, unexpected T_FUNCTION in /in/fmS6q on line 27
Process exited with code 255.
Output for 5.0.0 - 5.0.5: Parse error: parse error, unexpected T_ARRAY, expecting '&' or T_VARIABLE in /in/fmS6q on line 3
Process exited with code 255.
Output for 4.4.2 - 4.4.9: Parse error: syntax error, unexpected T_ARRAY, expecting '&' or T_VARIABLE or T_CONST in /in/fmS6q on line 3
Process exited with code 255.
Output for 4.3.0 - 4.3.1, 4.3.5 - 4.3.11, 4.4.0 - 4.4.1: Parse error: parse error, unexpected T_ARRAY, expecting '&' or T_VARIABLE or T_CONST in /in/fmS6q on line 3
Process exited with code 255.
Output for 4.3.2 - 4.3.4: Parse error: parse error, expecting `'&'' or `T_VARIABLE' or `T_CONST' in /in/fmS6q on line 3
Process exited with code 255.

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