Maps

Whamm provides maps for storage of key-value pairs. This is similar to java's Map and python's dict types. In fact, it is exactly Rust's HashMap type...since Whamm leverages this Rust type under-the-hood!

Instantiation

// No need to instantiate a map, it is automatically created as an empty map.
var a: map<i32, i32>;

Reading and writing elements

Reading and writing elements of maps uses the [ ... ] syntax like maps in many other languages.

var a: map<i32, i32>;
a[0] = 3; // map write
var b: i32 = a[0]; // map read

// maps can also contain tuples!
var c: map<(i32, i32, i32), i32>;
c[(0, 0, 0)] = 3; // map write
var b: i32 = c[(0, 0, 0)]; // map read

Bounds and null checks

Accesses of Whamm maps are dynamically checked against the bounds.

var a: map<i32, i32>;
var b: i32 = a[0]; // produces Wasm trap through Rust