Mecabで取り扱う名詞と接尾語を連結させる

<?php
$mecab = new MeCab_Tagger();
$last_posid = false;
for ($node = $mecab->parseToNode($str); $node; $node = $node->getNext()) {
if (($last_posid == 46 || $last_posid == 47) && ($node->posid == 46 || $node->posid == 47)) {
// 前後が地名同士ならば連結させる
$tokens[count($tokens) - 1]["surface"] .= $node->getSurface();
}
elseif ($node->posid == 56) {
// 接尾語だった場合は、前の名詞に連結させる
$tokens[count($tokens) - 1]["surface"] .= $node->getSurface();
}
else {
$tokens[] = array(
"id"      => $node->getId(),
"surface" => $node->getSurface(),
"posid"   => $node->posid,
"stat"    => $node->getStat(),
"length"  => $node->getLength(),
"feature" => split(",", $node->getFeature()),
);
$last_posid = $node->posid;
}
}