Lesson 1: Go setup and toolchain: Concept walkthrough

Concept Explanation

This lesson gives you a practical first look at the Go toolchain and the shape of a minimal Go program. You will run a small file, see how package declarations and imports fit together, and understand why Go favors a direct, readable style. By the end, you should be comfortable creating a tiny program, running it from the terminal, and recognizing the basic structure you will reuse in later lessons.

Where to Put the Code

1. Define color and position variables at the top.
2. Create shape drawing or placement logic in the middle.
3. Render output (print, canvas, SVG, or styled block) at the end.

Command Reference

• Run `go version` to confirm that Go is installed and available in your terminal.
• Use `go run main.go` for quick experiments while you are still learning the basics.
• Use `go build` when you want to create an executable and verify the code compiles cleanly.
• Notice how `package`, `import`, and `func main()` define the smallest runnable Go program.

Step-by-step Guide

1. Create a new file named `main.go` and type the example yourself instead of pasting it.
2. Run the file once and confirm that the terminal prints the expected message.
3. Change the printed sentence to something personal so you can verify your edit actually ran.
4. Add a second `fmt.Println` line and check that the output appears in the same order.
5. Finish by explaining, in one short sentence, what `main()` does in a Go program.

Practice Exercises

• Write a program that prints your name and the word `learning Go` on separate lines.
• Create a version of the example that prints three short status messages in order.
• Make a tiny startup message for a command-line tool, then run it with `go run`.

Coding Challenges

• Deliberately remove the `import` line, run the file, read the compiler message, then fix it.
• Create a clean two-file workspace for experiments and explain which file Go actually runs.

Mini Practice Tasks

• Rename the printed message and rerun the program.
• Add one more output line without breaking the file structure.
• Describe the purpose of `package main` in plain English.