在模板中使用函数代替方法

Question

I use the following code

var data struct {
    File FZR
    API  API
}


const tmpl = `
    {{- range .File.Modules}}
     # in context of {{.Name}}

        echo {{.EchoText}}
    {{end}}`

func  EchoText(m mts) string {
    return m.Type
}

and like this its not working, now I change it to

func (m mts) EchoText() string {
    return m.Type
} 

it will work but I want to make it work with the first option, how can I do it ? I mean update the template ...

update: as approva answer https://golang.org/pkg/text/template/#example_Template_func

but there is only string, how can I register the EchoText

Answer 1

As @mkopriva suggested in his first comment you just have to reference all your functions into a template.FuncMap where you establish the mapping from names to functions

Then into the template you just need to call them passing them the mts as parameter.

package main

import (
    "log"
    "os"
    "text/template"
)

type mts struct {
    Type1 string
    Type2 string
}

func main() {
    funcMap := template.FuncMap{
        "myFunc1": EchoType1,
        "myFunc2": EchoType2,
    }

    const templateText = `
Input: {{printf "%q" .}}
Output1:{{myFunc1 .}}
Output2:{{myFunc2 .}}
`

    tmpl, err := template.New("myFuncTest").Funcs(funcMap).Parse(templateText)
    if err != nil {
        log.Fatalf("parsing: %s", err)
    }

    myMts := mts{Type1: "myType1", Type2: "myType2"}
    err = tmpl.Execute(os.Stdout, myMts)
    if err != nil {
        log.Fatalf("execution: %s", err)
    }
}

func EchoType1(m mts) string {
    return m.Type1
}

func EchoType2(m mts) string {
    return m.Type2
}

This will produce the following output :

Input: {"myType1" "myType2"}

Output1:myType1

Output2:myType2