Post with X comments per post

Comment.php

<?php
class Comment extends Eloquent
{
        public function post()
        {
                return $this->belongsTo('Post');
        }
        public function scopePerPost($query, $limit) {
                $ids = Cache::remember('paged_comment_ids', 10, function() use ($limit) {
                        $ids = array();
                        foreach(Comment::lists('post_id', 'id') as $comment_id => $post_id)
                        {
                                if ( ! array_key_exists($post_id, $ids) ) $ids[$post_id] = array();
                                if ( count($ids[$post_id]) < $limit ) $ids[$post_id][] = $comment_id;
                        }
                        return array_unique( array_flatten($ids) );
                });
                return $query->whereIn('id', $ids);
        }
}

Post.php

<?php
class Post extends Eloquent
{
        public function comments()
        {
                return $this->hasMany('Comment');
        }
}

routes.php

<?php

Route::get('comments', function() { return Comment::with('post')->get(); });
Route::get('posts', function() { return Post::with('comments')->get(); });
Route::get('page', function() {
        return Post::with(array('comments' => function($query) {
                $query->perPost(3);
        }))->get();
});