@ 2014-10-26T16:28:26Z <?php
/*
span :: (a -> Bool) -> [a] -> ([a],[a])
span _ xs@[] = (xs, xs)
span p xs@(x:xs')
| p x = let (ys,zs) = span p xs' in (x:ys,zs)
| otherwise = ([],xs)
*/
function span($p, $xs) {
if (empty($xs)) {
return [[], []];
}
$xs_ = $xs;
$x = array_shift($xs_);
if ($p($x)) {
list($ys, $zs) = span($p, $xs_);
return [array_merge([$x], $ys), $zs];
}
return [[], $xs];
}
/*
groupBy :: (a -> a -> Bool) -> [a] -> [[a]]
groupBy _ [] = []
groupBy eq (x:xs) = (x:ys) : groupBy eq zs
where (ys,zs) = span (eq x) xs
*/
function array_group(callable $eq, array $xs) {
if (empty($xs)) {
return [];
}
$x = array_shift($xs);
// curry of $eq
$eqx = function ($y) use ($eq, $x) { return $eq($x, $y); };
list($ys, $zs) = span($eqx, $xs);
return array_merge([array_merge([$x], $ys)], array_group($eq, $zs));
}
function it($m,$p){echo ($p?'OK':'NO')." It $m\n"; if(!$p){$GLOBALS['f']=1;}}function done(){if(@$GLOBALS['f'])die(1);}
it('spans elements which match', span(function ($x) { return $x < 3; }, [1, 2, 3]) === [[1, 2], [3]]);
it('spans elements which match from the start', span(function ($x) { return $x == 3; }, [1, 2, 3, 3]) === [[], [1, 2, 3, 3]]);
it('spans returns empty lists on empty list', span(function ($x) { return false; }, []) === [[], []]);
it('groups elements recursively', array_group(function ($a, $b) { return $a === $b; }, [1, 1, 2, 1]) === [[1, 1], [2], [1]]);
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Output for 5.4.0 - 5.4.45 , 5.5.0 - 5.5.38 , 5.6.0 - 5.6.28 , 7.0.0 - 7.0.20 , 7.1.0 - 7.1.10 , 7.2.0 - 7.2.33 , 7.3.16 - 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 OK It spans elements which match
OK It spans elements which match from the start
OK It spans returns empty lists on empty list
OK It groups elements recursively
Output for 4.4.2 - 4.4.9 , 5.1.0 - 5.1.6 , 5.2.0 - 5.2.17 , 5.3.0 - 5.3.29 Parse error: syntax error, unexpected '[' in /in/tQEUQ on line 12
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 , 5.0.0 - 5.0.5 Parse error: parse error, unexpected '[' in /in/tQEUQ on line 12
Process exited with code 255 . Output for 4.3.2 - 4.3.4 Parse error: parse error in /in/tQEUQ on line 12
Process exited with code 255 . preferences:dark mode live preview
243.05 ms | 401 KiB | 352 Q