How to do it...

These steps cover writing and running your application:

1. From your Terminal or console application, create a new directory called ~/projects/go-programming-cookbook/chapter2/ansicolor.
2. Navigate to this directory.

3. Run the following command:

$ go mod init github.com/PacktPublishing/Go-Programming-Cookbook-Second-Edition/chapter2/ansicolor

You should see a file called go.mod that contains the following:

module github.com/PacktPublishing/Go-Programming-Cookbook-Second-Edition/chapter2/ansicolor   

4. Copy tests from ~/projects/go-programming-cookbook-original/chapter2/ansicolor, or use this as an opportunity to write some of your own code!
5. Create a file called color.go with the following contents:

        package ansicolor

        import "fmt"

        //Color of text
        type Color int

        const (
            // ColorNone is default
            ColorNone = iota
            // Red colored text
            Red
            // Green colored text
            Green
            // Yellow colored text
            Yellow
            // Blue colored text
            Blue
            // Magenta colored text
            Magenta
            // Cyan colored text
            Cyan
            // White colored text
            White
            // Black colored text
            Black Color = -1
        )

        // ColorText holds a string and its color
        type ColorText struct {
            TextColor Color
            Text      string
        }

        func (r *ColorText) String() string {
            if r.TextColor == ColorNone {
                return r.Text
            }

            value := 30
            if r.TextColor != Black {
                value += int(r.TextColor)
            }
            return fmt.Sprintf("33[0;%dm%s33[0m", value, r.Text)
        }

6. Create a new directory named example and navigate to it.
7. Create a main.go file with the following contents:

        package main

        import (
            "fmt"

            "github.com/PacktPublishing/
             Go-Programming-Cookbook-Second-Edition/
             chapter2/ansicolor"
        )

        func main() {
            r := ansicolor.ColorText{
                TextColor: ansicolor.Red,
                Text:      "I'm red!",
            }

            fmt.Println(r.String())

            r.TextColor = ansicolor.Green
            r.Text = "Now I'm green!"

            fmt.Println(r.String())

            r.TextColor = ansicolor.ColorNone
            r.Text = "Back to normal..."

            fmt.Println(r.String())
        }

8. Run go run main.go.
9. You may also run the following commands:

$ go build
$ ./example

10. You should see the following output with the text colored if your Terminal supports the ANSI coloring format:

$ go run main.go
I'm red!
Now I'm green!
Back to normal...

11. If you copied or wrote your own tests, go up one directory and run go test. Ensure that all the tests pass.