• You can initialize common collection types with relatively little code
• Vec [v], HashMap {k=>v} and HashSet !{k} have been implemented

• Ordinary element: [foo, 1, 2i32]
• for each: [*(i; for i in 0..10)]
• for each and filter: [*(i; for i in 0..10; if i != 5)]
• for each and filter and sub for each: [*(i + j; for i in 0..10; if i != 5; for j in 1..i)]

• Ordinary element: {k => v, [k1]: v1}
• String ordinary key: {%[key]: "jack"} (key: String)
• Ident key: {name: "jack"} (name: &'static str)
• String ident key: {%name: "jack"} (name: String)
• Variable key: {*key: "jack"} (let key = "name";)
• Literal key: {"name": "jack"}
• Literal key tostring: {%"name": "jack"} (name: String)
• for each: Just like in Vec, but slightly different. e.g {*(i => i+1; for i in 0..5)}

• for each reserve: [*[10](i; for i in 0..10)]
• generic params: <i64>[1, 2, 3]
• init with capacity: (20)[1, 2, 3] | <i64>(20)[1, 2, 3]
• inspect block: [*(i; for i in 0..10; {dbg!(i);} if i & 1 == 0)]

crate: https://crates.io/crates/set_derive

# use set_derive::set_derive;
# use std::collections::HashMap;
let arr1 = vec![
    0, 1, 8, 9, 10, 15, 16, 17, 18, 19,
];
let arr2 = set_derive!([
    0, 1,
    *(i; for i in 8..=10),
    *(i; for i in 15..20),
]);
// python: [0, 1, *range(8, 10+1), *range(15, 20)]
assert_eq!(arr1, arr2);

let arr = set_derive!([*(
    i+j;
    for i in 0..6;
    if i%2!=0;
    for j in 0..i;
)]);
// python: [i+j for i in range(6) if i%2 for j in range(0, i)]
assert_eq!(arr, vec![1, 3, 4, 5, 5, 6, 7, 8, 9]);

let age_key = "age";
let jack = set_derive!({
    name: "jack",
    *age_key: "20",
});
assert_eq!(jack, HashMap::from([("name", "jack"), ("age", "20")]));