Until now, the chapter has covered the rudimentary concepts of the Go package; now it is time to dive deeper and look at the creation of Go code contained in packages. One of the main purposes of a Go package is to abstract out and aggregate common logic into sharable code units. Earlier in the chapter, it was mentioned that a group of Go source files in a directory is considered to be a package. While this is technically true, there is more to the concept of a Go package than just shoving a bunch of files in a directory.
To help illustrate the creation of our first packages, we will enlist the use of example source code found in github.com/vladimirvivien/learning-go/ch06. The code in that directory defines a set of functions to help calculate electrical values using Ohm's Law. The following shows the layout of the directories that make up the packages for the example (assuming they are saved in some workspace directory $GOPATH/src):
github.com/vladimirvivien/learning-go... |