Generics on Notes

Types, Interfaces & Composition

Sun, 04 Oct 2026 00:00:00 +0000

Syntax at a glance

Types come after names, there are no semicolons, and nothing has to live in a class.

package domain

// CodeAlphabet omits visually ambiguous characters (0/O, 1/I/L).
const CodeAlphabet = "ABCDEFGHJKMNPQRSTUVWXYZ23456789"
const CodeLength = 6

type RandomCodes struct{}

func (RandomCodes) Generate() string {
    b := make([]byte, CodeLength)
    rand.Read(b)
    for i := range b {
        b[i] = CodeAlphabet[int(b[i])%len(CodeAlphabet)]
    }
    return string(b)
}

:= declares and infers the type, inside functions only.
var x T declares a variable holding the zero value of T. Zero values are meant to be useful: an empty bytes.Buffer or sync.Mutex works without initialisation.
Exported = starts with a capital letter. That’s the only visibility rule.

Structs + methods instead of classes

Data and behaviour are declared separately. Constructors are plain functions.