On Tuesday, October 31, 2017 20:36:57 Jacob Carlborg via Digitalmars-d-learn wrote: > On 2017-10-31 16:36, Dr. Assembly wrote: > > thanks. I just find it werid, maybe because I came from C/C++ > > background, where it means only integer types. So enum s = "foo"; is > > really werid. But I'll get used to it. > > Think of it more like #define in C/C++ than "const". The above defines a > manifest constant that are only available at compile time, i.e. you > cannot take the address of a manifest constant.
Yeah, thinking about them as const would be bad. All enums (whether they're manifest constants or actual enum types) effectively get copy-pasted when they're used, and in the case of arrays, that can be really important to understand. String literals aren't a problem, but an enum that is any other type of dynamic array is going to end up allocating a new array every time you use it, whereas if you had a variable at module-scope or a static variable (regardless of whether the variable was mutable, const, or immutable), then there's an actual memory location involved, and the copy-pasting doesn't happen. But enums in general in D (both manifest constants and actual enum types) can be more than just int (though string is probably the most common aside from int). They can be pretty much any type whose values can be known at compile time, even including things like structs. So, while enum types _are_ int by default just like in C, D's enums are actually _way_ more powerful than C's enums. - Jonathan M Davis