Call a method from a Go template

go go-templates
Blacksad picture Blacksad · Apr 18, 2012 · Viewed 28.9k times · Source

Let's say I have

type Person struct {
  Name string
}
func (p *Person) Label() string {
  return "This is " + p.Name
}

How can I use this method from a html/template ? I would need something like this in my template:

{{ .Label() }}

Answer

tux21b picture tux21b · Apr 18, 2012

Just omit the parentheses and it should be fine. Example:

package main

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

type Person string

func (p Person) Label() string {
    return "This is " + string(p)
}

func main() {
    tmpl, err := template.New("").Parse(`{{.Label}}`)
    if err != nil {
        log.Fatalf("Parse: %v", err)
    }
    tmpl.Execute(os.Stdout, Person("Bob"))
}

According to the documentation, you can call any method which returns one value (of any type) or two values if the second one is of type error. In the later case, Execute will return that error if it is non-nil and stop the execution of the template.

Related questions

Iterating through map in template

I am trying to display a list gym classes (Yoga, Pilates etc). For each class type there are several classes, so I want to group all the Yoga classes, and all the Pilates classes and so on. I made this …

Read More
Switch or if/elseif/else inside golang HTML templates

I have this struct : const ( paragraph_hypothesis = 1<<iota paragraph_attachment = 1<<iota paragraph_menu = 1<<iota ) type Paragraph struct { Type int // paragraph_hypothesis or paragraph_attachment or paragraph_menu } I want to display my paragraphs in …

Read More
Access a map value using a variable key in a Go template

How can I look up the value of a map by using a variable key without iterating? So one can lookup a constant key on variable map $x with $x.key1, but is it possible to do amap.$key?

Read More