title: url template tag in django template
body: <p>I was trying to use the url template tag in django, but no lucky,</p>
  
  <p>I defined my urls.py like this</p>
  
  <pre><code>urlpatterns = patterns('',
      url(r'^analyse/$',              views.home,  name="home"),
      url(r'^analyse/index.html',     views.index, name="index"),
      url(r'^analyse/setup.html',     views.setup, name="setup"),
      url(r'^analyse/show.html',      views.show,  name="show"),
      url(r'^analyse/generate.html',  views.generate, name="generate"),
  </code></pre>
  
  <p>I defined the url pattern in my view like this</p>
  
  <pre><code>{% url 'show'%}
  </code></pre>
  
  <p>then I got this error message</p>
  
  <blockquote>
    <p>Caught an exception while rendering:
    Reverse for ''show'' with arguments
    '()' and keyword arguments '{}' not
    found.</p>
    
    <p>Original Traceback (most recent call
    last):   File
    "/Library/Python/2.5/site-packages/django/template/debug.py",
    line 71, in render_node
        result = node.render(context)   File
    "/Library/Python/2.5/site-packages/django/template/defaulttags.py",
    line 155, in render
        nodelist.append(node.render(context)) 
    File
    "/Library/Python/2.5/site-packages/django/template/defaulttags.py",
    line 382, in render
        raise e NoReverseMatch: Reverse for ''show'' with arguments '()' and
    keyword arguments '{}' not found.</p>
  </blockquote>
  
  <p>I am wondering why django failed to render? what is the right way to define it in the tempalte? </p>