我正在为我的博客开发一个Sware filter插件。它应该拒绝在名为swears.txt. 以下是我在单贴页面上用于评论表单的代码：

<?php
if (isset($_POST[\'submit\'])) {
    echo \'Submitted\'; // for debugging purposes
    $swearsFile = \'swears.txt\';
    $swearsCntnt = file_get_contents($swearsFile);
    $swearList = explode("\\n", $swearsCntnt);
    $swearWords = "/";
    for ($i = 0; $i < count($swearList); ++$i) {
        if ($i == 0)
            $swearWords .= rtrim($swearList[$i]);
        else
            $swearWords .= "|" . rtrim($swearList[$i]);
    }
    $swearWords .= "/i";
    if (preg_match($swearWords, $_POST[\'comment\'])) {
        wp_die( __( \'<strong>ERROR</strong>: You have entered forbidden text. Please consider revising.\' ), 200 );
    }
}
?>

问题是，在我按下“发表评论”按钮后，除了提交的评论显示为新评论外，什么都没有发生。我使用echo来验证是否按下了Post Comment按钮，无论其下面的语句是否返回true，但什么都没有发生。如何让WordPress确认if (isset($_POST[\'submit\']))?

function my_filter_comment_for_swear_words( $comment_content ) {
    // Verify if $comment_content contains swear words here
    // return $comment_content if it doesn\'t contain forbidden words
    // or wp_die if it does
}
add_filter( \'pre_comment_content\', \'my_filter_comment_for_swear_words\' );