When related values need to travel together, define a struct. The `struct` keyword introduces a set of named, typed fields; each field is accessed with dot notation. A struct can stand alone as a one-off value, but giving it a type name makes the definition reusable. section 3.6 section 3.6.1
Listing 3.22 Using a type in a declaration
type person struct {
name string
age int
}
andy := person{
name: "Andy",
age: 42,
}
james := person{
name: "James",
age: 26,
}
fmt.Println(andy.name, andy.age) // output: Andy 42
fmt.Println(james.name, james.age) // output: James 26
A named `person` type gives two values the same field definitions. Its keyed literals supply field values, and dot notation reads them. section 3.6.1
A recipe measurement illustrates the design payoff: a `Measurement` struct groups a `Magnitude` and a `Unit` into one domain value. Fields can use built-in types, named types, or other structs. A keyed literal such as `Measurement{Magnitude: 200, Unit: Gram}` creates a value; omitting `Magnitude` leaves it at its zero value. Multiline literals require a trailing comma after the final field value. section 5.1.2 section 3.6
As the domain model grows:
- Use capitalized field names when other packages need access; lowercase names remain unexported. section 5.1.2
- Combine structs with named types, embedding, methods, interfaces, and collections to model recipe steps, ingredients, scaling, and grocery lists. section 5.6.2 section 5.7
