笔记：django自定义标签

from django import template
from django.template.base import Node, TemplateSyntaxError

register = template.Library()
'''
自定义标签 
应用/templatetags/模块名.py
settings的INSTALLED_APPS中加上user.模块名
html模板中需要{% load 模块名%}
'''
class CalIndexNum(Node):
    #计算视图列表中每行的序号
    def __init__(self,numList):
        self.numList = numList
    def render(self, context):
        realList = []
        try:
            for numobj in self.numList:
                realList.append(numobj.resolve(context))
        except:
            raise TemplateSyntaxError("tag error")
        try:
            return int(realList[0])*(int(realList[1])-1)+int(realList[2])
        except:
            return ''
@register.tag(name="calindex")
def muladdNums(parser, token):
    bits = token.contents.split()
    realList = [parser.compile_filter(x) for x in bits[1:]]
    return CalIndexNum(realList)