Type Promote

Things to know

The type promotion system in Hpt handles type conversions and operations between different numeric types. It is implemented in tensor-types crate.

Implementation

The implementation is straightforward. See here

Note

Current implementation only supports one type of promotion. Like u32 + i32 = i32. We may want to have multiple version of promotion. The user may want u32 + i32 = i64. Adding new version is straightforward and just simply using the existing code and do little modification.

How

create a new feature that the user can choose in file hpt-types/Cargo.toml

[features]
.. // features
default = [.., "normal_promote"]
normal_promote = []
// new_promote = []

Go to hpt-types/src/promotion, create a new folder, like new_promote/
create files under hpt-types/src/promotion/new_promote/ like how we create in hpt-types/src/promotion/normal_promote/, then write promotion logic for the new promote.
Go to lib.rs and add new mod in promotion mod

pub mod promotion {
    #[cfg(feature = "normal_promote")]
    pub(crate) mod normal_promote {
        ..
    }
    #[cfg(feature = "new_promote")]
    pub(crate) mod new_promote {
        ..
    }
    pub(crate) mod utils;
}

Adding feature for the promotion, the user enable the specific feature. Then they can use the specific type of promotion.