formtastic - how to prepopulate a string input with a value

Question

I'm building an app, where users can give comments by just leaving their email to the comment.

I want them to be able to register directly from there, by a link with their email adress as a param
(like: <%= link_to register_path(:email => @comment.email %> ) - so there is no existing user record yet.
this should be done by applying a value to the form.input field via the :value option.

But the following code doesn't work!

<%- if params[:email] -%>
  <%= f.input :email, :required => true, :value => params[:email] %>
<%- else -%>
  <%= f.input :email, :required => true %> 
<%- end -%>

I had a look inside the formtastic rdoc and inside my local gem but couldn't find any option for that.

Suggestions anyone?

Answer 1

sometimes the easiest things come to your mind by asking for them:

approach: do the job in the controller not the view!

if params[:email]
  @user = User.new(:email => params[:email])
else
  @user = User.new
end

sorry for bothering you!

Answer 2

Yup, you got the right answer all by yourself! Formtastic's rdoc is a mess, but we're working on it. Another option if you want this purely at a view level is to use the :inpput_html option, which gives you direct access to HTML attributes of the input tag:

f.input :email, :input_html => { :value => params[:email] }