在Go模板中，访问范围内的父/全局管道 [英] In Go templates, accessing parent/global pipeline within range

问题描述

在text/template包中的{{range pipeline}} T1 {{end}}动作中，是否可以在range动作之前访问管道值，还是可以将父/全局管道作为参数传递给Execute?

Is it possible, within a {{range pipeline}} T1 {{end}} action in the text/template package to access the pipelines value prior to the range action, or the parent/global pipeline passed as an argument to Execute?

工作示例，展示了我的工作尝试

Working example that shows what I try to do:

package main

import (
    "os"
    "text/template"
)

// .Path won't be accessible, because dot will be changed to the Files element
const page = `{{range .Files}}<script src="{{html .Path}}/js/{{html .}}"></script>{{end}}`

type scriptFiles struct {
    Path string
    Files []string
}

func main() {
    t := template.New("page")
    t = template.Must(t.Parse(page))

    t.Execute(os.Stdout, &scriptFiles{"/var/www", []string{"go.js", "lang.js"}})
}

play.golang.org

推荐答案

使用$变量(推荐)

从软件包文本/模板文档中:

执行开始时，将$设置为传递给Execute的data参数，即dot的起始值.

When execution begins, $ is set to the data argument passed to Execute, that is, to the starting value of dot.

正如@Sandy所指出的，因此可以使用$.Path访问外部作用域中的Path.

As @Sandy points out, it is therefore possible to access the Path in the outer scope using $.Path.

const page = `{{range .Files}}<script src="{{html $.Path}}/js/{{html .}}"></script>{{end}}`

使用自定义变量(旧答案)

发布后几分钟就找到了一个答案.
通过使用变量，可以将值传递到range范围:

Found one answer just minutes after posting.
By using a variable, a value can be passed into the range scope:

const page = `{{$p := .Path}}{{range .Files}}<script src="{{html $p}}/js/{{html .}}"></script>{{end}}`

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