Macro tp_npos_elections::generate_solution_type

generate_solution_type!() { /* proc-macro */ }

Generates a struct to store the election result in a small way. This can encode a structure which is the equivalent of a tp_npos_elections::Assignment<_>.

The following data types can be configured by the macro.

• The identifier of the voter. This can be any type that supports tetsy-scale-codec’s compact encoding.
• The identifier of the target. This can be any type that supports tetsy-scale-codec’s compact encoding.
• The accuracy of the ratios. This must be one of the PerThing types defined in arithmetic.

Moreover, the maximum number of edges per voter (distribution per assignment) also need to be specified. Attempting to convert from/to an assignment with more distributions will fail.

For example, the following generates a public struct with name TestSolution with u16 voter type, u8 target type and Perbill accuracy with maximum of 8 edges per voter.

generate_solution_type!(pub struct TestSolution<u16, u8, Perbill>::(8))

The given struct provides function to convert from/to Assignment:

• fn from_assignment<..>(..)
• fn into_assignment<..>(..)

The generated struct is by default deriving both Encode and Decode. This is okay but could lead to many 0s in the solution. If prefixed with #[compact], then a custom compact encoding for numbers will be used, similar to how tetsy-scale-codec’s Compact works.

generate_solution_type!(
    #[compact]
    pub struct TestSolutionCompact<u16, u8, Perbill>::(8)
)