src/Matchers/Trees/TrieRouteMatcher.php
private static function getMatchCandidates(
        TrieNode $node,
        array $segments,
        int $segmentIter,
        array $hostSegments,
        array &$routeVars
    ): iterable {
        // Base case.  We iterate to 1 past the past segments there are n + 1 levels of nodes due to the root node.
        if ($segmentIter === \count($segments)) {
            if ($node->hostTrie === null) {
                foreach ($node->routes as $route) {
                    yield new MatchedRouteCandidate($route, $routeVars);
                }
            } else {
                // We have to traverse the host trie now
                $routeVarsCopy = $routeVars;
                yield from self::getMatchCandidates($node->hostTrie, $hostSegments, 0, $hostSegments, $routeVarsCopy);
            }

            return;
        }

        $segment = $segments[$segmentIter];

        // Check for a literal segment match, and recursively check its descendants
        if (($childNode = ($node->literalChildrenByValue[\strtolower($segment)] ?? null)) !== null) {
            $routeVarsCopy = $routeVars;
            yield from self::getMatchCandidates($childNode, $segments, $segmentIter + 1, $hostSegments, $routeVarsCopy);
        }

        // If a variable child is a match, check its descendants
        foreach ($node->variableChildren as $childNode) {
            $routeVarsCopy = $routeVars;

            if ($childNode->isMatch($segment, $routeVarsCopy)) {
                yield from self::getMatchCandidates(
                    $childNode,
                    $segments,
                    $segmentIter + 1,
                    $hostSegments,
                    $routeVarsCopy
                );
            }
        }
    }
private static function getMatchCandidates(
        TrieNode $node,
        array $segments,
        int $segmentIter,
        array $hostSegments,
        array &$routeVars
    ): iterable {
        // Base case.  We iterate to 1 past the past segments there are n + 1 levels of nodes due to the root node.
        if ($segmentIter === \count($segments)) {
            if ($node->hostTrie === null) {
                foreach ($node->routes as $route) {
                    yield new MatchedRouteCandidate($route, $routeVars);
                }
            } else {
                // We have to traverse the host trie now
                $routeVarsCopy = $routeVars;
                yield from self::getMatchCandidates($node->hostTrie, $hostSegments, 0, $hostSegments, $routeVarsCopy);
            }

            return;
        }

        $segment = $segments[$segmentIter];

        // Check for a literal segment match, and recursively check its descendants
        if (($childNode = ($node->literalChildrenByValue[\strtolower($segment)] ?? null)) !== null) {
            $routeVarsCopy = $routeVars;
            yield from self::getMatchCandidates($childNode, $segments, $segmentIter + 1, $hostSegments, $routeVarsCopy);
        }

        // If a variable child is a match, check its descendants
        foreach ($node->variableChildren as $childNode) {
            $routeVarsCopy = $routeVars;

            if ($childNode->isMatch($segment, $routeVarsCopy)) {
                yield from self::getMatchCandidates(
                    $childNode,
                    $segments,
                    $segmentIter + 1,
                    $hostSegments,
                    $routeVarsCopy
                );
            }
        }
    }
Gets the list of matching route candidates for a particular node

This method uses generators that, given the order of the code, will return literal segments before variables
ones. Callers of this method will only attempt to descend the trie either on the first time or if previous
match candidates didn't meet constraints, hence saving us unnecessary descents down the trie.

@param TrieNode $node The current node
@param array $segments The list of URI segments to match
@param int $segmentIter The current index of segments
@param array $hostSegments The list of URI host segments, which will be traversed if there's a host trie
@param array $routeVars The mapping of route variable names to values
@return iterable|MatchedRouteCandidate[] The list of matched route candidates