References question

[north osprey]

&String is a reference to a pointer to text data on the heap.
&std is a reference to text data.

[tacit zealot]

&String
is

& ---> String
       ptr ----> actual data
       len
       cap

where &str is

&str
 ptr ---> actual data
 len

[hasty path]

ok that makes sense. so println!("{:p}", &q) is giving me the address of the String object (is that the word for it?). That itself contains the ptr and metadata.

[hasty path]

while &str is the address of the str data on the heap.

[tacit zealot]

(note that &str doesnt necessarily mean its pointing to the heap)

[hasty path]

you mean in the case of a static str?

[onyx wing]

Nope, &str is the address of str data somewhere. In the case of a literal it will be in static memory, in the case of an ArrayString or std::str::from_utf8 it could be on the stack, or in the case of String::as_str it would be on the heap.

[tacit zealot]

there's also the case of &str pointing to the stack

[hasty path]

ok nice I will read into stack allocated str. Btw is it correct to call String, the thing that contains the ptr + other data as an object? Or does it have a more technical name in Rust

[onyx wing]

Usually you can just talk about types and values in Rust. "object" isn't a term used much.

so "String::new() returns a value of type String"

[hasty path]

Is it correct to see String as like a wrapper or container over a pointer to the heap and some other data? I vaguely remember that terminology from somewhere.

[onyx wing]

The book calls "wrappers around pointers with Deref implementations" smart pointers, but I don't personally see that terminology used much.

[tacit zealot]

to be pedantic, String is just a wrapper to Vec<u8>. you can actually check the source code for this

[hasty path]

that makes sense since vec has a ptr, cap, len.