utility types

This crate use proc-macro to realize several utility types of Typescript in Rust.

macro	Typescript Utility Type
[Partial]	Partial<Type>
[Pick]	Pick<Type, Keys>
[Omit]	Omit<Type, Keys>
[Extract]	Extract<Type, Union>
[Exclude]	Exclude<UnionType, ExcludedMembers>

Example

Here is an example of how to use this crate.

use utility_types::{Omit, Partial, Pick, Required};
#[derive(Clone, Partial, Required, Pick, Omit)]
#[partial(ident = PartialFoo, derive(Debug, PartialEq))]
#[required(ident = RequiredFoo, derive(Debug, PartialEq))]
#[pick(arg(ident = PickAB, fields(a, b), derive(Debug, PartialEq)))]
#[omit(arg(ident = OmitCD, fields(c, d), derive(Debug, PartialEq)))]
pub struct Foo {
    a: u8,
    b: Option<u8>,
    c: Option<Vec<u8>>,
}

The above code will generate the following code.

#[derive(Debug, PartialEq)]
pub struct PartialFoo {
    a: Option<u8>,
    b: Option<Option<u8>>,
    c: Option<Option<Vec<u8>>>,
}
#[derive(Debug, PartialEq)]
pub struct RequiredFoo {
    a: u8,
    b: u8,
    c: Vec<u8>,
}
#[derive(Debug, PartialEq)]
pub struct PickAB {
    a: u8,
    b: Option<u8>,
}
#[derive(Debug, PartialEq)]
pub struct OmitCD {
    a: u8,
    b: Option<u8>,
}

Some useful traits are also generated:

• From<Foo> for PartialFoo, PickAB, OmitCD
• From<PartialFoo> for Foo

Known Issue

Currently I don't analyze which generic is used in the generated struct or enum. So rustc will complain if the field with generic is not included in the generated struct or enum.