创建html engine 提示"IsPositive" not defined
[ERRO] 2019/03/29 02:28 view: template: github.com/kataras/iris/_examples/tutorial/url-shortener/templates/index.html:16: function "IsPositive" not defined
panic: view: template: github.com/kataras/iris/_examples/tutorial/url-shortener/templates/index.html:16: function "IsPositive" not defined
goroutine 1 [running]:
main.main()