Module data_model 

The data model of Müsli.

Müsli supports the following fundamental types:

• Empty¹.
• Boolean values.
• Unsigned integers (corresponding to u8, u16, u32, u64, and u128).
• Signed integers (corresponding to i8, i16, i32, i64, and i128).
• Floats (corresponding to f32 and f64).
• Optional values².
• Bytes, a raw byte sequence.
• Strings, a byte sequence known to be a valid utf-8 string.
• Sequences³.
• Maps³. There is no restriction on the key, and they can contain duplicates.
• A variant³, which is a simple kind of container containing a key and a value. The key is the discriminant identifying the variant.

These are used as the basis to serialize any Rust type.

By default, Rust types are mapped like the following:

• Structs are serialized as maps, where the key is the #[musli(name =..)] of the field.
• Tuples are serialized as sequences.
• Enums are serialized as variants, where the key is the #[musli(name = ..)] of the variant.

To control the exact behavior of serialization, see the derives section.

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1. Empty values serve the purpose of acting as placeholder for things which have no value, such as the empty tuple () or PhantomData<T>. Encoders are free to treat them however they want to. For descriptive encoders where it’s possible, it’s typical for empty values to be skipped. ↩

2. This directly corresponds to the Option<T> type in Rust. While many formats internally handles optionality since it is a requirement to skip over unknown fields, this type is given special treatment to ensure that formats which are not descriptive can handle them. Without this, it would be impossible for the non-packed storage format to provide partial upgrade safety. ↩

3. There is no particular restriction that containers must contain uniform types. However, this is typically enforced by the types deriving Encode and Decode in Rust. ↩ ^1 2 3