Difference between Slice and Array

[ib00]

I thought I understood the idea of Slice (pointer + length), but then I got confused
when I saw that memory can be allocated for a slice.

So, what's the difference between slice and array?

[travisdoor]

Hi, the main difference is that arrays are allocated on the stack every time, that's why we have to specify the size in compile time i.e. foo: [2]s32. To simplify things the interface of an array and slice is the same, we have .len and .ptr, but internally the size (or length) of an array is stored in the type itself and when .len is used on an array, it is implicitly replaced by constant number.
The slice on the other hand can point to any memory and .len + .ptr are explicitly stored in struct { len: s64; ptr: *T; }