Notes about Go

go.md

Features

• Code not run on a VM (i.e. directly compiled to machine code).
• Automatic garbage collection.

Module

• Collection of packages versioned together (e.g. a simple go repo on Github).
• Defined by a go.mod file placed at its root directory.

Package

• Directory containing on or more .go source files.

Commands

$ go mod init github.com/h4k1m0u/repo  # Initialize a new module in the current directory (ie. creates a new go.mod file)
$ go run .  # Compile and run the main go package
$ go mod tidy  # Install remote packages by scanning code for imports

Notions

From A Tour of Go:

• Requirements for executables: a package named main and a function also named main (entry point of the program).

• A name (fct or var) in a package is exported only if it begins with capital letter.

• Types come after variable names.

• A function can return any number of results.

• It is possible to declare & initalize multiple variables on the same line.

• Short variable declaration (:=)

  • To declare and initialize a variable: s := "hello" (valid only in a function).

  • Equivalent to: var s string; s = "hello"

• Pointers: same principle as in C.

• Variables without an initial value are zero-initialized.

• Casting: var i int = 42; var f float64 = float64(i)

• Constants declared with: const world = "monde"