/**
* Gets an array of slices of size `$size` from an array.
* ```php
* $pairs = slices(2);
* $pairs([1, 2, 3, 4, 5]); // [[1, 2], [3, 4], [5]]
* $pairs("Hello World"); // ['He', 'll', 'o ', 'Wo', 'rl', 'd']
* slices(5, [1, 2]); // [[1, 2]]
* slices(3, []) // []
* slices(3, '') // ''
* ```
*
* @signature Number -> [a] -> [[a]]
* @signature Number -> String -> [String]
* @param int $size
* @param array $list
* @return array
*/
function slices()
{
$slices = function ($size, $list) {
if (empty($list)) {
return is_string($list) ? '' : [];
}
if (length($list) <= $size) {
return [$list];
}
return prepend(take($size, $list), slices($size, remove($size, $list)));
};
return apply(curry($slices), func_get_args());
}
/**
* Splits a string into chunks without spliting any group surrounded with some
* specified characters. `$surrounders` is a string where each pair of characters
* specifies the starting and ending characters of a group that should not be split.
* ```php
* $groups = chunks('(){}', ',');
* $groups('1,2,(3,4,5),{6,(7,8)},9'); // ['1', '2', '(3,4,5)', '{6,(7,8)}', '9']
*
* $names = chunks('()""', ' ');
* $names('Foo "Bar Baz" (Some other name)'); // ['Foo', 'Bar Baz', 'Some other name']
* ```
*
* @signature String -> String -> String -> [String]
* @param string $surrounders
* @param string $separator
* @param sring $text
* @return array
*/
function chunks()
{
$chunks = function ($surrounders, $separator, $text) {
// Let's assume some values to understand how this function works
// surrounders = '""{}()'
// separator = ' '
// $text = 'foo ("bar baz" alpha) beta'
$surrounders = map(slices(1), slices(2, $surrounders));
// [['"'. '"'], ['{'. '}'], ['(', ')']]
$openings = map(get(0), $surrounders);
// ['"', '{', '(']
$closings = map(get(1), $surrounders);
// ['"', '}', ')']
$numOfSurrounders = length($surrounders);
// 3
$indexes = keys($surrounders);
// [0, 1, 2]
$items = split($separator, $text);
// ['foo', '("bar', 'baz"', 'alpha)', 'beta']
// The initial state
$state = (object) ['chunks' => [], 'counts' => array_fill(0, $numOfSurrounders, 0), 'total' => 0];
// We will iterate over $items and update the $state while adding them
// For each item we need to update counts and chunks
// Updates count for a single surrender (the surrender at $index)
// $item : the item we are adding
// $counts : the previous counts
$updateCountAt = curry(function ($item, $counts, $index) use($openings, $closings) {
$count = occurences(__(), $item);
return $openings[$index] == $closings[$index] ? ($counts[$index] + $count($openings[$index])) % 2 : $counts[$index] + $count($openings[$index]) - $count($closings[$index]);
});
// Updates counts for all surrenders
$updateCounts = curry(function ($item, $counts) use($indexes, $updateCountAt) {
return map($updateCountAt($item, $counts), $indexes);
});
// Adds an item to the state and returns a new state
$addItem = function ($state, $item) use($separator, $updateCounts) {
$counts = $updateCounts($item, get('counts', $state));
$newChunks = 0 == $state->total ? append($item, $state->chunks) : append(last($state->chunks) . $separator . $item, init($state->chunks));
return (object) ['chunks' => $newChunks, 'counts' => $counts, 'total' => sum($counts)];
};
// Returns the chunks of the resulting state after adding all items
return get('chunks', reduce($addItem, $state, $items));
};
return apply(curry($chunks), func_get_args());
}
