protected static function __match(array $patterns)
    {
        return function (...$args) use ($patterns) {
            $parameterTypes = array_map(self::getType(), $args);

            try {
                $keysToValues = Arrays::zip(array_keys($patterns), array_values($patterns));

                list($key, $matchingPattern) = Arrays::first(
                    Pattern::patternApplies($parameterTypes, $args),
                    $keysToValues
                );
            } catch (ElementNotFoundException $e) {
                throw new IncompletePatternMatchException(
                    'Incomplete pattern match expression. (missing ' . implode(', ', $parameterTypes) . ')'
                );
            }


            /**
             * Upcoming Feature, Array DSL for matching via `x::xs` etc.
             */
//            // if key is a string, manually match
//            if (is_string($key)) {
//
//                throw new \Exception('Array DSL not available.');
//            }

            list($hasExtractable, $unwrappedArgs) = self::unwrapArgs($args);

            $value = $matchingPattern(...$args);
            $isCallable = is_callable($value);

            if ($hasExtractable && ! $isCallable) {
                throw new InvalidPatternMatchException(
                    'Invalid pattern match expression. (one of ' . implode(', ', $parameterTypes)
                    . ' requires a callback to unwrap)'
                );
            }

            /**
             * Extractable requires a callback to feed args into.
             */
            if ($hasExtractable && $isCallable) {
                return $matchingPattern(...$args)(...$unwrappedArgs);
            }

            /**
             * No extractable so we can just return the value directly.
             */
            return $value;
        };
    }