Day 4 - Go Packages

Today i want to check if my understandings of Go packages are correct:

(Reference: golang-packages)

1) There is only one package inside a subdirectory under $GOPATH
2) The package name has to be the same as the subdirectory name
3) The package can consist of any number of files
4) The filenames of the *.go files inside one package can be anything you choose


So i created a new directory for my test library package:

$GOPATH\src\github.com\<yourgithubusername>\rpcbotinterfaceobjects
which is in my case:
D:\goworkspace\src\github.com\kimxilxyong\rpcbotinterfaceobjects


Inside that directory i created two files:

1)  rpcbotinterfaceobjects_input.go

package rpcbotinterfaceobjects

type BotInput struct {

    Content string

}

func (this *BotInput) GetContent() string {

    return this.Content

}

func (this *BotInput) SetContent(NewContent string) {

    this.Content = NewContent

}

2)  rpcbotinterfaceobjects_output.go

package rpcbotinterfaceobjects

type BotOutput struct {

    Content string

}

func (this *BotOutput) GetContent() string {

    return this.Content

}

func (this *BotOutput) SetContent(NewContent string) {

    this.Content = NewContent

}

As you can see the package names are both the same, but the filenames can be anything you choose.

Next is to create the executable which uses this package in:

$GOPATH\src\github.com\<yourgithubusername>\packagetest
or in my case:
D:\goworkspace\src\github.com\kimxilxyong\packagetest

Create a file named test_my_package.go (or actually any name you want) and insert the following code into it:

package main

import (

    "fmt"

    // use the rpcbotinterfaceobjects package

    "github.com/kimxilxyong/rpcbotinterfaceobjects"

)

func main() {

    // Variable declaration for in and output objects

    var input rpcbotinterfaceobjects.BotInput

    var output rpcbotinterfaceobjects.BotOutput

    // Write test strings to the objects

    input.SetContent("rpcbotinterfaceobjects.Input_Content.test_my_package")

    output.SetContent("rpcbotinterfaceobjects.Output_Content.test_my_package")

    // Show the content of the objects

    fmt.Println(input.GetContent())

    fmt.Println(output.GetContent())

}

Open a cmd shell and cd into the packagetest directory.

Run  go install to build the executable, it will be put into your $GOPATH\bin folder.

Note: The bin will be named after your folder, not your *.go file!

Run packagetest

So far my assumptions 1-4 have been confirmed and additionally my tests seem to indicate that if you compile a file with func main() in it, the resulting exe is named like the directory your main comes from.

Maybe some of you may ask why I used this in the struct methods. Thats because I come from a Java and Delphi background and as this or self is not a  keyword in Go I just used it for better readability.

Quote:
Golang does not have a self or this keyword to reference to the current instance. In the method example of func (c *Circle) area() float64 the receiver struct is named "c". Use that variable name, rather than this to refer to the current instance.
oo-example-in-golang