As we've mentioned before, idiomatic Julia code typically consists of many small functions. Unlike most other language implementations, some of the core primitives in the base library are also implemented in Julia. All of this means that the overhead of a function call needs to be as low as possible for performant Julia code. This is partly ensured due to some aggressive inlining performed by the Julia compiler.
Inlining is an optimization performed by a compiler, where the contents of a function or method are inserted directly into the body of the caller of that function. Thus, instead of making a function call, execution continues by directly implementing the operations of the called function/method within the caller's body.
In addition, quite a few compiler optimization techniques only operate within the body of a single function. Inlining allows...