Validation errors from associated models

Hey guys,

I have a weird problem and I think you are able to solve it easy.

I have two models - "Posts" and "Comments". A post :has_many comments and a comment :belongs_to a post. I followed the guide on

so I added the following code to my Post-view:

    = form_for([@post, @post.comments.build]) do |f|       = f.label :author       = f.text_field :author       = f.label :content       = f.text_area :content       = f.submit

I added some validation to my Comments-model, so it looks like:

    class Comment < ActiveRecord::Base       belongs_to :post       validates_presence_of :author     end

My comments-controller looks like:

    class CommentsController < ApplicationController       def create         @post = Post.find(params[:post_id])         @comment = @post.comments.create(params[:comment])         redirect_to @post       end     end

Creating new comments works fine, and if I leave "author" empty the comment will not be saved. That's good. But now I wanna show the validation-errors. Normally I would do that with adding something like

    - if @comment.errors.any?       - @comment.errors.full_messages.each do |error|         = error

to the formular in the post-view, but of course @comment is undefine in that view.

How can I show the errors there?

Regards, Dennis