rails can‘t use code to generate form

Question

my view code(index.slim) is this:

-form_tag do
   Form contents

but this doesn't generate a form,nothing I will get,why?

my rails version is 3.2.14 .and I just generate this project through rails new blog to study rails.

Answer 1

Don't you have to use the outputting version of the form_tag helper?

= form_tag do