formtastic-ruby-wrapper.rb

class FormBuilder
  
  attr_reader :calls
  
  def initialize(&block)
    @calls = []
    @current = @calls
    block.call(self)
  end
    
  def method_missing(*args, &block)
    name = args.shift
    @current << [name, args, []]
    if block
      old_current = @current
      @current = @current.last.last
      block.call(self)
      @current = old_current
    end
  end
  
  def to_erb
    @indent = 0
    @erb = ""
    @calling_on = 'f'
    @calls.each do |c|
      method_to_erb(c)
    end
    @erb
  end
  
  def method_to_erb(c)
    has_block = c[2].any?
    options = c[1].last.is_a?(Hash) ? c[1].last : {}
    @erb << "#{@indent.times.collect{' '}}<%#{'=' unless has_block} #{@calling_on}.#{c[0]} #{c[1].collect{|a| a.inspect}.join(', ')} #{"do" if has_block} #{"|" + options[:for].to_s + "_form|" if options[:for]} %>\n"
    if has_block
      old_calling_on = @calling_on
      @calling_on = "#{options[:for].to_s}_form" if options[:for]
      @indent += 2
      c[2].each{|child| method_to_erb(child)}
      @indent -= 2
      @calling_on = old_calling_on 
      @erb << "<% end %>\n"
    end
  end
  
end

def form(&block)
  FormBuilder.new(&block)
end



user = form do |f|
  f.inputs "User Details" do
    f.input :username
    f.input :first_name
    f.input :last_name
    f.input :email
    f.input :roles, :as => :check_boxes, :collection => lambda{ User.find(:all) }
  end
  
  f.inputs "Password" do
    f.input :password, :type => :password
    f.input :password_confirmation, :type => :password
  end
  
  f.inputs "Avatar", :for => :avatar do |avatar_form|
    avatar_form.input :file
  end
  
  f.inputs "Admin Access", :if => lambda { current_user.has_permission?(:manage_users) } do
    f.input :admin, :label => "Give user admin privileges"
  end
  
  f.buttons
end

puts "User Form:"
puts user.to_erb
puts

post = form do |f|
  f.inputs :name => "Basic" do
    f.input :title
    f.input :body
    f.input :section
    f.input :publication_state, :as => :radio
    f.input :category
    f.input :allow_comments, :label => "Allow commenting on this article"
  end

  f.inputs :name => "Advanced" do
    f.input :keywords, :required => false, :hint => "Example: ruby, rails, fs"
    f.input :extract, :required => false
    f.input :description, :required => false
    f.input :url_title, :required => false
  end

  f.inputs :name => "Author", :for => :author do |author_form|
    author_form.input :first_name
    author_form.input :last_name
  end

  f.buttons do
    f.commit_button
  end
end

puts "Posts Form:"
puts post.to_erb
puts



other = form do |f|
  f.inputs "Basic", :id => "basic" do 
     f.input :title 
     f.input :body 
   end 
   f.inputs :name => "Advanced Options", :id => "advanced" do 
     f.input :slug, :label => "URL Title", :hint => "Created automatically if left blank", :required => false 
     f.input :section, :as => :radio 
     f.input :user, :label => "Author", :label_method => :full_name
     f.input :categories, :required => false 
     f.input :created_at, :as => :string, :label => "Publication Date", :required => false 
   end 
   f.buttons do 
     f.commit_button 
   end
end


puts "Other Form:"
puts user.to_erb