func WeekdayCN(args ...interface{}) string {
	weekdayCN := []string{"日", "一", "二", "三", "四", "五", "六"}

	var week int
	// 判断参数数量和类型
	switch len(args) {
	case 1:
		//单个参数，类型应该为 time.Time
		if t, ok := args[0].(time.Time); ok {
			week = Weekday(t)
		}
	case 2:
		// 两个参数，第一个为 string，第二个为 time.Time
		if dayStr, ok := args[0].(string); ok {
			weekdayCN[0] = dayStr
			if t, ok := args[1].(time.Time); ok {
				week = Weekday(t)
			}
		}
	default:
		// 多于一个参数，忽略
	}

	return weekdayCN[week]
}

package main

import (
	"html/template"
	"log"
	"os"
	"time"
)

func LastSunday() time.Time {
	now := time.Now()
	daysSinceSunday := int(now.Weekday())
	if daysSinceSunday != 0 {
		daysAgo := (daysSinceSunday + 7) % 7
		lastSunday := now.AddDate(0, 0, -daysAgo)
		return lastSunday
	}
	return now
}

func main() {
	// 创建一个新的模板
	tmpl := template.New("example")
	// 注册自定义函数
	tmpl.Funcs(template.FuncMap{
		"WeekdayCN": WeekdayCN,
		//"now":       time.Now,
		"now": LastSunday,
	})
	// 解析模板内容
	tmpl, err := tmpl.Parse(" {{now}}: 星期({{WeekdayCN now}})    星期({{ now | WeekdayCN }})  星期({{ WeekdayCN \"哈哈\" now}})   星期({{ now | WeekdayCN \"日\"}})  ")
	if err != nil {
		log.Fatal(err)
	}

	// 获取当前时间
	now := LastSunday()
	// 执行模板
	err = tmpl.Execute(os.Stdout, now)
	if err != nil {
		log.Fatal(err)
	}
}

func Weekday(date time.Time) int {
	return int(date.Weekday())
}

func WeekdayCN(args ...interface{}) string {
	weekdayCN := []string{"日", "一", "二", "三", "四", "五", "六"}

	var week int
	// 判断参数数量和类型
	switch len(args) {
	case 1:
		//单个参数，类型应该为 time.Time
		if t, ok := args[0].(time.Time); ok {
			week = Weekday(t)
		}
	case 2:
		// 两个参数，第一个为 string，第二个为 time.Time
		if dayStr, ok := args[0].(string); ok {
			weekdayCN[0] = dayStr
			if t, ok := args[1].(time.Time); ok {
				week = Weekday(t)
			}
		}
	default:
		// 其他情况，忽略
	}

	return weekdayCN[week]
}