Stdlib

@johnhenry/jth-stdlib is the standard library of the jth language — the ~110 operators covered operator-by-operator in the operator reference. This page is about the package: how it loads, what it does to the registry, and when you need to touch it at all.

npm install @johnhenry/jth-stdlib

You usually don’t import this yourself

Compiled jth programs import the stdlib automatically — the compiler preamble emits the import, so jth run and jth compile output already have every standard operator available. @johnhenry/jth-eval also loads it for you.

You import it explicitly in exactly one situation: driving @johnhenry/jth-runtime directly from JavaScript.

Importing registers globally — a side effect, on purpose

import "@johnhenry/jth-stdlib";   // that's the whole API

import { Stack, processN, registry } from "@johnhenry/jth-runtime";
const stack = new Stack();
await processN(stack, [10, 3, registry.resolve("-")]);
stack.peek(); // 7

The import’s side effect is the point: every operator lands in the global registry from @johnhenry/jth-runtime. Consequences worth knowing:

• Importing it twice is harmless; not importing it means registry.resolve throws UNKNOWN_OPERATOR for even +.
• Everything in the process shares one registry. If you need per-evaluation vocabularies or allowlists, that’s jth-eval’s ScopedRegistry and sandbox modes — see Embedding.
• The registry distinguishes static names from dynamic patterns. The stdlib registers both: named operators like map, and pattern factories that make 3+, 10log, *** work without pre-registering every numeral.

Category map

Full tables with examples live in the operator reference; this is the shape of the library:

Category	Examples
Arithmetic	+, -, *, /, %, **, ++, --, abs, sqrt
Variadic math	Σ, Π, min, max
Stack	swap, dupe, drop, over, rot, peek, clear, collect
Comparison	=, ==, !=, <, >, <=, >=, <=> (aliases eq?, lt?, …)
Logic	&&, ||, ~~/not, xor, nand, nor
Control flow	if, elseif, else, times, while, until, break, when
Error handling	try, throw, error?
String	strcat, strseq, upper, lower, trim, len, starts?, ends?
Type	typeof, number?, string?, array?, nil?, empty?, contains?
Array	push, pop, shift, unshift, map, filter, reduce, fold, bend
Dictionary	keys, values, entries, merge, record
Serialization	into-json, from-json, into-lines, from-lines
Combinators	each, fanout, zip, compose
Async	_ (await), __ (Promise.all)
Meta	apply/exec, $, $$, <<-, ->>
Iterator	iter, next, ..
Sequences	fibonacci
Statistics	mean, median, mode, modes
Hyperoperations	*** (tetration), **** (pentation)
Dynamic patterns	2+, 3*, 10log, …

What the stdlib deliberately leaves out

Console I/O is the stdlib’s only contact with the world outside the stack — peek and peek-all — which is why those two are exactly the set blocked by jth-eval’s "restricted" sandbox. There is no file, network, or process access in the standard vocabulary. Network-facing operators (for example the Ollama helpers in @johnhenry/jth-ai) are deliberately kept out of the default vocabulary and must be wired in explicitly from the JS host; HTML generation (@johnhenry/jth-html) is opt-in per program via ::import "@johnhenry/jth-html";.

Previously published as [email protected]; now @johnhenry/jth-stdlib with the version restarted at 0.0.0 on scope adoption.