Question

（唯一的区别是，在第二个版本中，我试图用parens（）调用form_form，第一个例子我没有使用parens。）我知道我可以清理我这样做的方式，但是被另一个线索所覆盖。

这项工作：

<%= form_for (@quiz_attempt.blank? ?  QuizAttempt.new(:patient_id => current_user.id, :started => Time.now.utc, :step_quiz_id => @course_step.step.step_quiz.id) : @quiz_attempt), :url => submit_quiz_course_course_step_path(@course_step.course, @course_step) do |f| %>

但这不是:(尝试使用form_for作为函数form_for（）

<%= form_for ((@quiz_attempt.blank? ?  QuizAttempt.new(:patient_id => current_user.id, :started => Time.now.utc, :step_quiz_id => @course_step.step.step_quiz.id) : @quiz_attempt), :url => submit_quiz_course_course_step_path(@course_step.course, @course_step)) do |f| %>

错误

ERROR:/Users/cmuench/rails_projects/infosurge/app/views/course_steps/show_quiz.html.erb:10: syntax error, unexpected ',', expecting ')'
...step_quiz.id) : @quiz_attempt), :url => submit_quiz_course_c...
...                               ^
/Users/cmuench/rails_projects/infosurge/app/views/course_steps/show_quiz.html.erb:10: syntax error, unexpected ')', expecting keyword_end
...rse_step.course, @course_step)) do |f| @output_buffer.safe_c...
...                               ^
/Users/cmuench/rails_projects/infosurge/app/views/course_steps/show_quiz.html.erb:27: syntax error, unexpected keyword_ensure, expecting $end
Extracted source (around line #10):

7:     <p><%= @course_step.step.step_quiz.instructions %> </p>
8:   </div>
9: <div id="Quiz">
10:     <%= form_for ((@quiz_attempt.blank? ?  QuizAttempt.new(:patient_id => current_user.id, :started => Time.now.utc, :step_quiz_id => @course_step.step.step_quiz.id) : @quiz_attempt), :url => submit_quiz_course_course_step_path(@course_step.course, @course_step)) do |f| %>
11:     <%= render :partial => 'shared/error_messages', :object => f.object %>
12:         <% @course_step.step.step_quiz.step_quiz_questions.each do |quiz_question| %>
13:             <h3><%= quiz_question.value %></h3>
Trace of template inclusion: app/views/course_steps/show_quiz.html.erb

Answer 1

我不知道为什么解析器无法识别您要执行的操作。

为什么不尝试使代码可读，而不是试图找出ruby解析器的所有复杂性？

最简单的方法可能是使用||=运算符，并将此逻辑移动到控制器中。

比较第一个示例的扩展形式：

Controller: 

 Not Shown

View:

<%= form_for (
    (@quiz_attempt.blank? ?  
      QuizAttempt.new(
        :patient_id => current_user.id, 
        :started => Time.now.utc, 
        :step_quiz_id => @course_step.step.step_quiz.id) : 
      @quiz_attempt
    ),
  :url => submit_quiz_course_course_step_path(@course_step.course, @course_step)
             ) do |f| %>

致：

Controller:
#... near the end of the relevant action
@quiz_attempt ||= QuizAttempt.new(:patient_id => current_user.id, 
                                  :started => Time.now.utc, 
                                 :step_quiz_id => @course_step.step.step_quiz.id)

View:

<%= form_for @quiz_attempt, :url => 
submit_quiz_course_course_step_path(@course_step.course, @course_step) do |f| %>

这样你可以使用no-parens样式而不会让令人困惑的?:位堵塞一切。

希望有所帮助。

*顺便说一句，这是：

我认为出了什么问题

form_for()不一定与form_for ()相同，因此可能会对您是否试图说出来感到困惑

“调用form_for，结果为(@quiz_attempt, :url => url) #which is not valid syntax”

或

“使用参数form_for调用(@quiz_attempt, {:url => url}) #which is what the real arguments look like。

Ruby on rails form_for oddness

1 个答案: