Macro validation_rules 

macro_rules! validation_rules {
    ($(
        $rule_name:ident: |$param:ident: $type:ty| $condition:expr
    ),* $(,)?) => { ... };
}

Macro for creating type-safe validation rules

Examples

use sklears_core::validation_rules;

validation_rules! {
    positive: |x: f64| x > 0.0,
    probability: |x: f64| x >= 0.0 && x <= 1.0,
    non_empty: |s: &str| !s.is_empty()
}