serde-cs

serde-cs is a small, focused Rust crate that provides a serde wrapper for comma-separated lists. It lets you serialize a collection into a single comma-joined string and deserialize such a string back into a typed collection, handling empty segments gracefully.

The crate exposes a simple CS<T> newtype for both Vec and fixed-size array targets, integrating cleanly with any serde format such as serde_json. It is ideal for query parameters, CSV-like fields, and other places where a delimited string needs to map to a typed Rust collection.

What You Get

• A CS<T> newtype in the vec module for serializing/deserializing Vec<T> as a comma-separated string.
• An array-oriented variant in the array module for fixed-size collections.
• Graceful handling of empty and repeated delimiters (e.g. ",,1,,2,," parses to [1, 2]).
• Format-agnostic behavior that works with serde_json and other serde data formats.
• A tiny dependency footprint (only serde) with doc-tested examples.

Common Use Cases

• Deserializing comma-separated query-string parameters into a typed Vec.
• Storing a list of values as a single delimited string field and reading it back.
• Round-tripping CSV-like values through any serde format.
• Accepting flexible, whitespace/empty-tolerant delimited input in an API.

Under The Hood

Architecture — The crate is intentionally minimal: lib.rs documents the API and re-exports two modules, vec.rs implementing the CS<T> newtype over Vec<T> and array.rs implementing the fixed-size array variant. Serialization joins elements with commas into a single string; deserialization splits on commas, skips empty segments, and parses each remaining token into T via serde, surfacing an error if any token fails to parse.

Tech Stack — Pure Rust, edition 2021, with a single runtime dependency on serde 1 and serde_json used only as a dev-dependency for the doc-tests. Categorized under encoding on crates.io and dual-licensed MIT OR Apache-2.0.

Code Quality — At roughly 12 KB of Rust across three files, the crate is small enough to audit at a glance. Behavior is specified and verified through extensive doc-tests in lib.rs covering empty lists, repeated delimiters, and parse failures; there are no separate unit-test modules but the doc examples serve as the executable spec.

API Design — The API is about as simple as it gets: wrap a collection in CS(...) and hand it to any serde serializer/deserializer. There is essentially no learning curve for anyone already using serde, and the CS newtype pattern keeps the delimited-string behavior opt-in and explicit rather than global.