A field is a named component declared in a composite type; every instance of that type stores values for its fields. In Julia, field type annotations specify what each component can hold. Unlike dictionary entries, fields are fixed by the type, and instances cannot add or remove them at runtime. section 7.1 section 18.4
Listing 7.1 Definition of a composite type
struct Archer
name::String #1
health::Int #2
arrows::Int #3
end
An Archer type declares three fields, each with a name and a type. section 7.1
Reading fields
An Archer instance stores a name, health, and arrow count. Read a value with dot access, as in robin.name or robin.arrows. section 7.1
