Which of these code styles do you find preferable?
First option using mut with constructor in the beginning:
let mut post_form = PostInsertForm::new(
data.name.trim().to_string(),
local_user_view.person.id,
data.community_id,
);
post_form.url = url.map(Into::into);
post_form.body = body;
post_form.alt_text = data.alt_text.clone();
post_form.nsfw = data.nsfw;
post_form.language_id = language_id;
Second option without mut and constructor at the end:
let post_form = PostInsertForm {
url: url.map(Into::into),
body,
alt_text: data.alt_text.clone(),
nsfw: data.nsfw,
language_id,
..PostInsertForm::new(
data.name.trim().to_string(),
local_user_view.person.id,
data.community_id,
)
};
You can see the full PR here: https://github.com/LemmyNet/lemmy/pull/5037/files
You must log in or register to comment.
Neither.
- make
new()give you a fully valid and usable struct value. - or use a builder (you can call it something else like Partial/Incomplete/whatever) struct so you can’t accidentally do anything without a fully initialized value.
Maybe you should also use substructs that hold some of the info.
- make
100% the second one. It’s the idiomatic way to do this in Rust, and it leaves you with an immutable object.
I personally like to move the short declarations together (i.e. body down with language_id (or both at the top)) but that’s a minor quibble.
Definitely the second one.
- It avoids Mut
- It makes clear that the initialization is over at the end of of the statement. The first option invites people to change some more properties hundreds of lines down where you won’t see them.
I prefer to encapsulate a mutable reference to the instance in a scope.
let post_form = { let mut post_form = PostInsertForm::new( // your constructor arguments ); post_form.some_mutating_method( // mutation arguments ); post_form };This way you’re left with an immutable instance and you encapsulate all of the logic needed to setup the instance in one place.
