Appendix E — Standard library modules

Part IX (chapters 32–37) toured the standard library by use. This appendix is a reference, one page per module, gathering what each does, which ops it offers and what it does not do. It is not a place to read from the start but a place to open when needed.

Module pages share one shape. The head gives the source file, layer and capabilities received, followed by what the module does, its ops at a glance, how to use it, design and boundaries, and what is not built. The maturity each module writes (experimental, incubating, standard) is authoritatively in the source head and the development repository’s ledger and moves between editions, so it is not copied here. The conventions every module follows — the caller’s buffer, failure as a value, all or nothing, ownership that must be settled — are in chapter 32.

Module names may differ from file names. What use looks for is the module declaration in the file (lib/str.low is strings, lib/alloc.low is allocs). Cross-module names are always called qualified (strings.find), and a frequently used one can get an alias with use codec as c ..

Module	In one line
strings	String view operations — cut, find, compare
strbuf	Owned string buffer and null-terminated cstr
fmt	Formatting assembled into the caller’s buffer
utf8	UTF-8 code point iteration and validation
utf16	UTF-16 surrogate arithmetic
unicode	Unicode property tables — extracted mechanically
codec	Hex · base64
regex	Pike VM regular expressions without backtracking
term	The pure half of a terminal renderer — ANSI assembly · screen diff · width
sortlib	In-place quicksort for u64
sortgen	Generic sort — the type brings the comparison
searchlib	Binary search over sorted slices
hashmap	u64 → u64 open addressing
strmap	Byte string → u64 hash map
vecs	Growing byte vector
spsc	Lock-free single-producer single-consumer ring buffer
hash	Hash-map slots (FNV-1a) · damage detection (CRC-32) · SHA-256
math	Floating-point maths — close instead of ==
random	Separates reproducible sequences from OS entropy by name
hmac	HMAC-SHA256 · HKDF — who sent it
chacha	ChaCha20 stream — not safe alone
poly	Poly1305 — a fresh key per message
aead	ChaCha20-Poly1305 seal and open — cryptography starts here
x25519	Key agreement
aes	AES-128 block cipher — usually wrong used alone
gcm	AES-128-GCM — never repeat a nonce
bigint	Big-number modular arithmetic
rsa	RSASSA-PSS verification
p256	NIST P-256 curve and ECDSA verification
p384	NIST P-384 curve and ECDSA verification — the public web’s intermediates
ecdsa	ECDSA P-256 signing — nonce derived without randomness
ed25519	Ed25519 signature verification
der	Minimal DER parser — extracts public keys only
pem	Unwrapping PEM envelopes
x509	Reading X.509 certificates — offsets and lengths only
verify	Certificate signatures and one link of a chain
tls13	TLS 1.3 parts — key schedule · records · transcript · Finished
tlssrv	Server TLS handshake and application data records
tlscli	Client TLS 1.3 handshake — the caller checks certificates
http	HTTP/1.1 request parser — its heart is rejection
soa	A trial of laying structs out as per-field arrays

Table 50.1 — L0 — pure computation (effects none · the caller’s buffer)

Module	In one line
allocs	Allocator trait · bump allocators · two default allocators
pool	Generational-handle block pool
shard	Tokens splitting storage into non-overlapping pieces
budget	Bit budgets for handles and retiring generations
wire	Fields in one word — a mask carries position and width
flags	Named on/off settings in one word
segarena	Fixed-size segment arena
pagecache	Page ids and pin tokens
growvec	Growing byte vector — short name for vecgen.vec u8
vecgen	Generic growing vector vec t
mapgen	Generic hash map table k v
nodelist	Fixed-size intrusive list
segview	Cursor, total length and flattening for scattered views
lifemode	lifemode · lifeatom — when a value ends

Table 50.2 — L1 — storage (needs the allocation capability or borrowed bytes)

Module	In one line
io	Stream reading over slices
outbuf	Buffered output — forgetting to flush is rejected
files	Files and directories — forgetting to close is rejected
tty	Terminal input — raw mode · reading keys · pure key parsing
net	Sockets — TCP loopback · in-process connection pairs
clock	Time and deadlines — monotonic and wall clocks
trust	Finding a trusted root in the trust store — the bundle is streamed

Table 50.3 — L2 — host (needs capabilities)

The cryptographic modules are stacked in layers towards TLS 1.3; that order and the top that does not exist yet are in chapter 36.