Django解析变量的作用是什么?(template.variable)

@register.tag
def my_tag(parser, token):
    # This version uses a regular expression to parse tag contents.
    try:
        # Splitting by None == splitting by spaces.
        tag_name, var_name = token.contents.split(None, 1)
    except ValueError:
        raise template.TemplateSyntaxError, "%r tag requires arguments" % token.contents.split()[0]
    #this will "bind" the variable in the template to the actual_var object
    actual_var = template.Variable(var_name)
    return MyNode(template_variable)


class MyNode(template.Node):
    def __init__(self, actual_var):
        self.actual_var = actual_var

    def render(self, context):
        actual_var_value = self.actual_var.resolve(context)
        #do something with it
        return result

from django.template import RequestContext
def my_view(request):
    #request stuff
    return render_to_response("mytemplate.html", {'extra context': None,}, context_instance=RequestContext(request))

@register.tag
def simple_request_aware_tag(parser, token):
    return SimpleRequestAwareNode()

class SimpleRequestAwareNode(template.Node):
    def render(self, context):
        request = template.Variable('request').resolve(context)
        #we want to return the current username for example
        return request.user.get_full_name()

resolve_variable

Resolves a variable