UPDATE: This post has become unstable due to migration, I don't think it'll be any use.

As usual I'm still playing with Merb and I would like to share Merb's partial. Basically its the ability to render objects using a template file that could be used inside several other templates. Hmm.. I hope that went well.

To give you a quick example, lets say your building a blog with a controller named posts and got a posts folder inside your views which contains new.html.erb and edit.html.erb. Your new.html.erb might contain something like:

Add new post

Now in our edit form, those fields are common so it makes more sense (atleast on our example) to use partials. To create a partial, we're going to create _form.html.erb on the same folder as our new.html.erb and edit.html.erb.

There's nothing fancy in here, we're just checking if a post is being pass. If we have a post, we set its value otherwise leave it as an empty string.

Now we can modify our new.html.erb:

Add new post

and edit.html.erb:

Edit new post

As you can see, we call the partial function and pass a symbols that's the same as our partial view.  Our optional parameter :with holds what ever value we want to pass on our partial view and this will be accessible via the partial's view name which is form.