The rails Rails form_tag and form_for helpers do not work as expected (Rails 1.2.1, Markaby 0.5 plugin). Here's some Markaby code to illustrate the problems (the first two forms illustrate the broken behavior, the second two show workarounds):

p 'form_for BROKEN'
form_for(:article, :url => article_path(@article), :html => { :method => :put }) do |f|
  f.text_field(:title)          # BROKEN: Outputs nil.
  submit_tag "Update"           # OK
end

p 'form_tag BROKEN'
form_tag(article_path(@article), :method => :put) do
  text_field(:article, :title)  # BROKEN: Outputs into separate form.
  submit_tag('Update')          # OK
end

p 'form_for OK'
form_for(:article, :url => article_path(@article), :html => { :method => :put }) do |f|
  self << f.text_field(:title)  # OK.
  submit_tag "Update"           # OK
end

p 'form_tag OK'
form_tag(article_path(@article), :method => :put) do
  div do
    text_field(:article, :title)  # OK.
    submit_tag('Update')          # OK
  end
end

PS: Thanks for the lovely templating language -- I just can't go back to ERB after using Markaby.

Creating sub-templates using content_for doesn't seem to work when used with rhtml templates. e.g.

application.rhtml
  h1 'application'
  <%= @content_for_layout %>

members.mab
  @content = @content_for_layout
  @content_for_layout = nil

  content_for('layout') do
    h2 'members'
    self << @content
  end

  render 'layouts/application', :content_for_layout=@content_for_layout

members/index.mab
  h3 'index'

With the above, application and index get rendered, but for some reason not members. If I change application.rhtml to a Markaby template, it works.