add more lifetime/generics support for o2o

[vnghia]

This is my attempt for #16.

[vnghia]

@Artem-Romanenia please take a look at this

[Artem-Romanenia]

Hi, thanks a lot for a PR! I will look into it as soon as I have a chance, maybe today, definitely before weekend.

[vnghia]

Hey it seems that you dont run cargo format and cargo clippy. I would like to propose another PR to do that. Is that good for you ? After this PR obviously.

[Artem-Romanenia]

Hi, thanks again for a contribution! I have a couple of notes though.

Generally, if there are Entity and EntityDto, I'm trying to make it so that o2o macro can be applied on any of them, for whatever conversion you may want. In this case, you've covered this scenario:

use o2o::o2o;

pub struct Entity {
    pub some_a: String,
    pub some_b: String,
}

#[derive(o2o)]
#[from_ref(Entity)]
pub struct EntityDto<'a, 'b> {
    #[from(~.as_str())]
    pub some_a: &'a str,
    #[from(~.as_str())]
    pub some_b: &'b str,
}

But I would also like to support something like this:

use o2o::o2o;

#[derive(o2o)]
#[ref_into(EntityDto<'a, 'b>)]
pub struct Entity {
    #[into(~.as_str())]
    pub some_a: String,
    #[into(~.as_str())]
    pub some_b: String,
}

pub struct EntityDto<'a, 'b> {    
    pub some_a: &'a str,
    pub some_b: &'b str,
}

Other than that, I would only ask you to add some tests in o2o-tests package (my tests are mess, so you just can loosely imitate what's going on there 😄). And also, when editing readme, I use "Markdown All in One" extension in VS Code, which syncronizes table of content. You can try using that or something similar, or I will just make some final touches to readme myself in the end, if you don't want to bother with this 😄

[vnghia]

Hi, could you merge this PR first and run rustfmt and I will send the new PR to support that case ? Because to support this case I will have to do a lot of changes but everytime I press Ctrl+S, my vscode will auto format the file which introduces unrelated changes and make it hard for reviewing 😅

[Artem-Romanenia]

So, the problem here is that default formatting sometimes goes against my personal preferences, however unconventional they are 😄 (mainly, I often value vertical compactness over horizontal, since mostly I do rust on 34'' widescreen and I have no problems with long lines). But here's an idea. I've created features/lifetimes branch. Please edit this PR or create a new one to merge your changes there instead of main. I will accept it and do rustfmt (is it the same thing as cargo fmt?). Then later I can figure out how to configure custom formatting rules specific to this project and reformat again.

[vnghia]

There are a lot of thing you can config with rustfmt or cargo fmt (I think it is the same). You can see all the config here https://github.com/rust-lang/rustfmt/blob/master/Configurations.md and I think you will find mainly max_width and comment_with and use_small_heuristics useful. In your case I think you can just put these lines inside rustfmt.toml, run rustfmt and call it a day

max_width = 400
newline_style = "Unix"
use_small_heuristics = "Max"

[Artem-Romanenia]

Ok, I guess no harm if I do it as you've originally suggested. But I'll do the configuration later, as I currently don't have access to my regular setup.

[Artem-Romanenia]

I've just added a commit with formatting to main, you should be good to go (hopefully 😄)