attrsets

Have you ever wanted to, say, define a few different serde serializations for the same structures?

Well, you could always write two versions of a struct, and std::mem::transmute between them to get different serializations:

```rust

[derive(Deserialize, Serialize)]

pub struct Thing { pub flag: bool, pub time: DateTime, }

[derive(Deserialize, Serialize)]

pub struct ThingCompact { #[serde(rename = "f")] pub flag: bool,

#[serde(with = "ts_seconds")]
#[serde(rename = "t")]
pub time: DateTime<Utc>,

} ```

But that's unmaintainable! >_<

This procedural macro automates this process:

```rust

[attrsets::attrsets(Compact)]

[derive(Deserialize, Serialize)]

pub struct Thing { #[attrset(Compact, serde(rename = "f"))] pub flag: bool,

#[attrset(Compact, serde(with = "ts_seconds"))]
#[attrset(Compact, serde(rename = "t"))]
pub time: DateTime<Utc>,

} ```

This example would basically expand into the above.

Every identifier in the attrsets attribute defines a suffix for a new version of the struct. The attrset field attribute wraps any other attribute, only including it in the provided list of variants (comma separated). Use _ for the plain non-suffixed variant e.g.:

```rust

[attrsets::attrsets(Readable)]

[derive(Deserialize, Serialize)]

pub struct Thing { #[attrset(_, serde(rename = "f"))] pub flag: bool,

#[attrset(_, serde(with = "ts_seconds"))]
#[attrset(_, serde(rename = "t"))]
pub time: DateTime<Utc>,

} ```

Limitations

• errors are not nice
• no way to propagate the variant choices to nested structs yet
  • of course you can just parameterize the structs and define nice aliases like type PostR = PostReadable<ImageReadable<GeoReadable>>

License

This is free and unencumbered software released into the public domain.
For more information, please refer to the UNLICENSE file or unlicense.org.