Eta

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Hash Maps and Hash Sets

Overview

Eta now ships native hash-map and hash-set runtime types with immutable update operations (assoc/dissoc style). The core builtins are available in every module, and std.hashmap / std.hashset add convenience helpers.

Key points:

Quick Start

(module demo
  (import std.hashmap std.hashset std.io)
  (begin
    (define m (hash-map 'a 1 'b 2))
    (define m2 (hash-map-assoc m 'c 3))
    (println (hash-map-ref m2 'b))
    (println (hash-map-size m2))

    (define s (hash-set 'x 'y))
    (define s2 (hash-set-add s 'z))
    (println (hash-set-contains? s2 'z))
    (println (hash-set-size s2))))

Core Hash-Map Builtins

FunctionSignature
hash-map(k1 v1 k2 v2 ...) -> map
make-hash-map() -> map
hash-map?(x) -> bool
hash-map-ref(m k [default]) -> value
hash-map-assoc(m k v) -> map
hash-map-dissoc(m k) -> map
hash-map-keys(m) -> list
hash-map-values(m) -> list
hash-map-size(m) -> int
hash-map->list(m) -> list
list->hash-map(xs) -> map
hash-map-fold(f init m) -> value
hash(x) -> int

Core Hash-Set Builtins

FunctionSignature
make-hash-set() -> set
hash-set(x1 x2 ...) -> set
hash-set?(x) -> bool
hash-set-add(s x) -> set
hash-set-remove(s x) -> set
hash-set-contains?(s x) -> bool
hash-set-union(a b) -> set
hash-set-intersect(a b) -> set
hash-set-diff(a b) -> set
hash-set->list(s) -> list
list->hash-set(xs) -> set

stdlib Wrappers

std.hashmap adds:

std.hashset adds:

Notes