Language Basics

Dynamic value model

HHY is dynamically typed. Runtime values include Null, Bool, Int, Float, String, List, Map, Range, DateTime, Path, Duration, Bytes, Percent, Result, Stream, and system objects.

• let declares a binding that cannot be reassigned.
• let mut declares a reassignable binding.
• Blocks, functions, and modules use lexical scope.
• Collection updates return new values; there is no in-place collection API.

Functions and control flow

fn summarize(items) {
    let mut total = 0

    for item in items {
        if item.enabled {
            total = total + item.score
        }
    }

    return total
}

let users = [
    { name: "Ada", enabled: true, score: 98 },
    { name: "Linus", enabled: false, score: 86 }
]

summarize(users) |> print

Functions receive values and support closures. V1.0 has no overloading, generics, or default parameters.