Standard Library and Packages

The region runtime: pages, regions, the frame pages the compiler gives every routine that allocates, and the traps a program raises on a bounds violation, a null unwrap or a lack of memory.

String and StringBuilder; Slice[T], the borrowed view that never owns; Vector[T] of a fixed length, Array[T] that grows, List[T]; HashMap[K, V] and HashSet[T] with their builders; Option[T] (written T?) and Result[T, E]. Indexing with [] traps outside the bounds, get(i) answers an Option, and put(i, v) writes.

Fibers, the scheduler and the evented I/O beneath the operating-system module, the task pool a self-scaling for runs on, threads and channels.

Console, File, Directory, Path and Tcp, and the process environment.

Channels between processes over TCP: a region sent to another node moves with its whole object graph.

A tape for reverse-mode differentiation — matrix products, activations, attention, the optimizers — living in one region per tape.

The protocol that gives the operators their binding strength (Expressions), generated from the levels of the grammar, and and and or on bool, whose right operand is lazy.

An HTTP/1.1 and HTTP/2 server with a router, static files, WebSocket and gRPC; the same server over TLS 1.3; and HTTP/3 over QUIC (ngtcp2).

TLS 1.3 for a TCP stream, bound to OpenSSL, and the hashes and key derivations a protocol above it needs.

RFC 8259 JSON: a pull reader, a value tree built on it, and a writer.

gzip for HTTP bodies, over libdeflate.

Clients of PostgreSQL (protocol version 3, SCRAM authentication, prepared statements, a pool), Redis (RESP2), SQLite (its own library) and Microsoft SQL Server (TDS 7.4).

A tensor tape resident on the GPU (Metal).