title: Why are user-defined types as fast and compact as built-in language types in Julia?
body: <p>I have reviewed a lot of documentation but I can not find a specific answer to this.</p>
  
  <p><strong>Julia</strong> standard primitive types are all defined in the language itself and that Julia lets you declare your own primitive types, but I do not know if that's the reason why a type defined by a programmer is as fast and compact as the built-in ones. I've even checked the source code on GitHub, more specifically <a href="https://github.com/JuliaLang/julia/blob/master/base/boot.jl" rel="nofollow noreferrer">bool.jl</a>
  that is where the numerical types as int are defined, but I do not dare to make speculations.
  Can someone give me a specific answer please? Thanks.</p>