On Wed, Oct 28, 2020 at 09:54:19PM +0000, Jan Hönig via Digitalmars-d-learn wrote: > Maybe this is a silly question, but I don't understand completely the > difference between an `enum` and a `shared immutable`. > > I could have: > > enum x = 1; > > or > > shared immutable x = 1; > > What is the exact difference between those too? [...]
An enum only exists at compile-time, and does not occupy any space. Each time it's referenced, a new instance of the value is created. (This is why it's a bad idea to use enum with an array literal, because every time it's referenced you get a new copy of the array.) A shared immutable is initialized at compile-time, and occupies space in the object file / runtime memory. It's also a single instance, and referencing it causes a load of this instance at runtime. It's not copied unless it's a by-value type, so an array literal will get stored as an array in the executable, and every time you reference it you get a slice of it instead of a copy. T -- In order to understand recursion you must first understand recursion.
