module Posgra::TemplateHelper
  def include_template(template_name, context = {})
    tmplt = @context.templates[template_name.to_s]

    unless tmplt
      raise "Template `#{template_name}` is not defined"
    end

    context_orig = @context
    @context = @context.merge(context)
    instance_eval(&tmplt)
    @context = context_orig
  end

  def context
    @context
  end
end