Macro select

macro_rules! select {
    (where $x:ident in $xs:expr => $cond:expr) => { ... };
    (unique $x:ident in $xs:expr => $cond:expr) => { ... };
    (duplicates $x:ident in $xs:expr) => { ... };
    ($($t:tt)*) => { ... };
}

Extracts values from an iterator using declarative logic-based syntax.

This macro provides a clean syntax for filtering and selecting values. It expands to corresponding select_* functions.

Modes

• select!(where x in xs => condition) — equivalent to select_where(xs, |x| condition)
• select!(unique x in xs) — equivalent to select_unique(xs)
• select!(duplicates x in xs) — equivalent to select_duplicates(xs)

Examples

use quantor::select;

let xs = vec![1, 2, 3, 4, 4];

let evens    = select!(where x in &xs => x % 2 == 0);
let uniques  = select!(unique x in &xs => *x > 0);
let dups     = select!(duplicates x in &xs);