Custom Package

Let's write a package to import and use in hellogo.

Create a sibling directory at the same level as the hellogo directory:

mkdir mystrings
cd mystrings

Initialize a module:

go mod init {REMOTE}/{USERNAME}/mystrings

Then create a new file mystrings.go in that directory and paste the following code:

// by convention, we name our package the same as the directory
package mystrings

// Reverse reverses a string left to right
// Notice that we need to capitlize the first letter of the function
// If we don't then we won't be able access this function outside of the
// mystrings package
func Reverse(s string) string {
  result := ""
  for _, v := range s {
    result = string(v) + result
  }
  return result
}

Note that there is no main.go or func main() in this package.

go build won't build an executable from a library package. However, go build will still compile the package and save it to our local build cache. It's useful for checking for compile errors.

Run:

go build