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go

How to get name of current package in go?


Is there a way to get on runtime the name of current package?

package main

import "fmt"

func main() {
    pkgName := {some magic here:)}
    fmt.Println(pkgName)
}

... and the result should be "main"

Right now I'm using constant like:

package main

import "fmt"
const (
    pkgName = "main"
)

func main() {
    fmt.Println(pkgName)
}

but I'm curious if you can avoid this


Solution

  • There is no runtime or reflect method or function that provides the functionality that you are looking for.

    The closest thing I could find is:

    package main
    
    import (
        "azul3d.org/lmath.v1"
        "fmt"
        "reflect"
    )
    
    type Empty struct{}
    
    func main() {
        fmt.Println(reflect.TypeOf(Empty{}).PkgPath())
        fmt.Println(reflect.TypeOf(lmath.Vec3{0, 0, 0}).PkgPath())
    }
    

    This would output:

    main
    azul3d.org/lmath.v1
    

    You could also read the first line of the file and remove the "package" substring. (Not sure if it's the best idea)

    package main
    
    import (
        "bufio"
        "bytes"
        "fmt"
        "os"
    )
    
    func main() {
        file, err := os.Open("so.go")
        if err != nil {
            panic(err)
        }
        r := bufio.NewReader(file)
        line, _, err := r.ReadLine()
        if err != nil {
            panic(err)
        }
        packageName := bytes.TrimPrefix(line, []byte("package "))
        fmt.Println(string(packageName))
    }