ejs递归函数的问题

ejs中可以声明递归函数吗？代码如下，createTree是一个递归函数。

<% function createTree(ret){ %>
      <% if(ret.comments){ %>
        <% var i = -1, len = ret.comments.length %>
        <% while(++i < len){ %>
          <% if(ret.comments[i].comments) { %>
          <% console.log(ret.comments[i]); %>
          <div class="media" id="<%= ret.comments[i]._id %>">
            <a class="pull-left">
              <img class="media-object" src="<%= ret.comments[i].gravatar %>">
            </a>
            <div class="media-body">
              <h4 class="media-heading text-muted "><a href="<%= ret.comments[i].site %>" rel="nofollow"><%= ret.comments[i].name %></a>于<%= ret.comments[i].create_time %>说道:</h4>
              <div class="comment"><%= ret.comments[i].comment %></div>
              <% createTree(ret.comments[i]); %>
            </div>
            <div class="btn btn-info btn-xs reply">回复</div>
          </div>
          <% }　else { %>
          <% console.log(ret.comments[i]); %>
          <div class="media" id="<%= ret.comments[i]._id %>">
            <a class="pull-left">
              <img class="media-object" src="<%= ret.comments[i].gravatar %>">
            </a>
            <div class="media-body">
              <h4 class="media-heading text-muted "><a href="<%= ret.comments[i].site %>" rel="nofollow"><%= ret.comments[i].name %></a>于<%= ret.comments[i].create_time %>说道:</h4>
              <div class="comment"><%= ret.comments[i].comment %></div>
            </div>
            <div class="btn btn-info btn-xs reply">回复</div>
          </div>
          <% } %>
        <% } %>
      <% } %>
    <% } %>