Julia 1.0 Programming Complete Reference Guide

Mutable composite types

It is also possible (and equally easy) to construct mutable composite types. The only thing we need to do is to use the mutable struct statement, instead of just struct:

julia> mutable struct Player 
           username::String 
           score::Int 
       end 

Our Player object should be mutable, as we'll need to update the score property after each game:

julia> me = Player("adrian", 0) 
Player("adrian", 0) 
 
julia> me.score += 10 
10 
 
julia> me 
Player("adrian", 10)