Use serde instead of rustc-serialize ? about mdbook

[dtolnay]

@gambhiro that doesn't seem like a fair comparison because you are not including any of the other dependencies.

On my computer a build following cargo clean takes 68 seconds without serde_codegen and 115 seconds with serde_codegen, but subsequent builds take 9 seconds either way. When iterating you only care about the 9 second time which is the same for both.

[kbknapp]

serde is super nice when used in the nightly branch because you can simply mark your structs as #[derive(Serialize)] or #[derive(Deserialize)] and then encode/decode them to any format supported by serde (I used JSON, but I hear YAML is being worked on too). It worked perfectly!

The downside is you're limited to the nightly branch. serde can be used on stable, but you end up implementing those traits yourself (which isn't too hard, but it is work).

Beyond that, I don't have a lot of knowledge about the differences :\

[azerupi]

Ok thanks for the clarification!
I will probably wait until all the features are in stable then, and focus on the other things in the meantime.

[gambhiro]

Just for reference, this is waiting for rust-lang/rust/issues/29597 and rust-lang/rust/issues/29644 to land in stable.

[azerupi]

I think it would be OK to make the jump now. Serde is becoming the defacto serialiser / deserialiser even though some ergonomic features are only available on nightly.

I think there are 2 ways we can make it work:

• Using serde_codegen
• Manual implementation

Code gen is obviously more convenient but requires some extra work in the build script. Which is not a big deal.

[gambhiro]

I followed the serde readme and made an experiment in this branch, refactoring only bookconfig.rs.

Although it works, the build time has become quite long, 1.5 mins instead of 9 secs.

With codegen:

cargo build  86.78s user 0.57s system 99% cpu 1:27.37 total

while before:

cargo build  8.93s user 0.37s system 99% cpu 9.327 total

I didn't PR because I think it's not worth the long feedback time while working. The feature tickets are apparently being worked on, I suggest waiting until they arrive in the stable release.

[azerupi]

That is a reasonable choice, thanks for looking into it :)

[gambhiro]

@dtolnay Thanks for explaining. I'm quite new to the rust build tools.