title: ruby on rails code syntax including some haml and model view control
body: <p>I have following  piece of code. Here is the original post
  <a href="https://stackoverflow.com/questions/9646815/conditionally-setting-css-style-from-ruby-controller">Conditionally setting CSS style from ruby controller</a></p>
  
  <pre><code>%th{:class =&gt; @title_header}= link_to 'Title', my_path(:sort =&gt; 'title'), :id =&gt; 'title_header'
  </code></pre>
  
  <p>I know that  the link_to work<br></p>
  
  <p>1.I dont understand what is :class and is :class a keyword?<br></p>
  
  <p>2.I understand that when we create a model and we will get a model_path,
  but in this case why we can pass an argument into my_path? <br></p>
  
  <p>3.Is that :sort also a keyword in rails?</p>
  
  <p>4.is :id a keyword in rails?</p>
  
  <p>5.so in this case , what we doing with my_path? is it going to return something?</p>
  
  <p>6.how about the :id, what it does in this case??</p>
  
  <p>Thankyou!</p>