BFCollections is a collection (ha! get it?) of collections classes for PHP 5.3+. They should make your code cleaner, more concise, and more correct.

They include:

• BFArray: A better array. It can be used just like a native array but it also has methods for common array operations such as map, filter, and reduceLeft.
• Option: Indicates an optional return result, via the form of an instance of the Some class or the global $None. Inspired by Scala's Option (naturally) and Haskell's Maybe. There are basic methods to operate on the values.
• Box: Again indicates an optional return result, though the lack of a value can also be indicated and even chained. Inspired by the Lift framework's Box.
• PartialFunction: Again Scala inspired, partial functions are functions that do not have output for every possible input and that are easily combined or composed. The Wikipedia page on partial functions has more on the mathematical theory.

Partial Function Examples

PartialFunctions do a very simple form of pattern matching by either testing input, either for strict equality (===) against the condition or as a true result when processed by the callable condition.

$f = pf(
  pfCase(function ($i) { return is_integer($i); }, function ($i) { return "$i is an integer"; }),
  pfCase("test", function ($str) { return "$str == test"; })
);
var_dump($f->isDefinedAt(1)); // -> bool(true)
print($f("test")); // -> test == test

$f2 = $f->orElse(pf(
  pfCase($always, function () {
    return "Our wildcard catch got the following arguments: " . print_r(func_get_args(), true);
  })
));
print($f2(1, 2, 3)); // -> Our wildcard catch got the following arguments: Array ( [0] => 1 [1] => 2 [2] => 3 )

$f3 = $f2->andThen(function ($result) { return "<p><strong>$result</strong></p>"; });
print($f3(1412)); // -> <p><strong>1412 is an integer</strong></p>