buffer
std/buffer — flat numeric buffers.
A [Point] is an array of references to Point objects rather than a flat run of coordinates: WasmGC has no unboxed aggregates inside arrays, which the specification records as a known consequence. For numeric work where the layout matters, a buffer is a flat sequence of numbers with the shape written down separately — which is what a layout engine or a renderer wants anyway.
This is the version over slices. A buffer.F64 over linear memory would let the host read it without copying, and is what the canvas renderer will want; nothing in the language stops it, but the Wasm backend has no linear memory today and adding one for this alone would cost every program the bytes.
F64
struct F64A flat run of floats, read and written in fixed-size records.
pub var values: [float]pub stride: int— How many numbers make up one record: 2 for a point, 4 for a rectangle.
f64
pub fn f64(stride: int) -> F64count
pub fn count(b: F64) -> intHow many records the buffer holds.
get
pub fn get(b: F64, record: int, field: int) -> floatOne number of one record.
record
pub fn record(b: F64, index: int) -> [float]A whole record, as a slice of stride numbers.
push
pub fn push(b: F64, values: [float]) -> F64A buffer with one record appended. Buffers are values, like slices: this produces a new one rather than editing the one it was given.
set
pub fn set(b: F64, record: int, field: int, value: float) -> F64A buffer with one number replaced.
column
pub fn column(b: F64, field: int) -> [float]Every value of one field, across every record — the column form, which is what a bounds check or a sum wants.
extent
pub fn extent(b: F64, field: int) -> (float, float)The smallest and largest value in a field.