Examples

The repo ships eleven numbered example programs in examples/, ordered as a learning path. Every one runs in CI through the real CLI. To run them yourself:

git clone https://github.com/johnhenry/jth && cd jth
npm ci && npm run build
npm run examples      # all of them, in order
npm run example:09    # just FizzBuzz

Or, with the CLI installed globally, jth run examples/09-fizzbuzz.jth.

The programs

01-hello.jth — Hello World: push a string, peek it. Two tokens of ceremony, total.

02-arithmetic.jth — The arithmetic operators, chained computation (2 3 + 4 * — the stack replaces parentheses), increment/decrement, and abs/sqrt/floor/ceil.

03-arrays.jth — The array toolkit end to end: literals, push/pop/shift/unshift, spread (...) and collect as inverses, then map/filter/reduce/fold and two bend unfolds (a range, powers of two). Also demonstrates the tidy-as-you-go drop habit that keeps variadic operators honest.

04-definitions.jth — Building vocabulary with :name: square and cube, a PI constant, operators calling operators (fourth-power), and a hypotenuse built from square swap square + sqrt.

05-dynamic-ops.jth — Number-prefixed operators (3+, 2*, 10log) with the trap spelled out in runnable form: the prefix is the left operand, so 20 3- is 3 - 20 = -17. Ends with the pipeline style these were made for.

06-error-handling.jth — try/throw/error? as data flow: errors become stack values, and a check-error definition branches on error? with the swap-into-if pattern.

07-fibonacci.jth — The built-in fibonacci step operator ((a, b) → (b, a, a+b)) driven by times, with the swap drop idiom that trims the stack back to two values each iteration.

08-factorial.jth — Iterative factorial with a distinctly stack-flavored strategy: lay out n, n-1, …, 1 using times, then collapse the whole stack with variadic Π.

09-fizzbuzz.jth — FizzBuzz 1–100 using the flat if/elseif/else chain — the canonical multi-way-branch example, plus a counter loop built from times.

10-statistics.jth — The variadic statistics set (mean, median, mode, modes) plus Σ, Π, min, max — each demonstration starting from a fresh stack, because these operators consume everything.

11-html.jth — A complete HTML page built with @johnhenry/jth-html, demonstrating the opt-in op-package mechanism (::import "@johnhenry/jth-html";), nested h-tag blocks, h-void + h-attrs for <meta charset>, and h-render. The CI end-to-end test asserts its exact output.

Reading order

01 → 05 are the language core in dependency order; 06 adds failure handling; 07 → 10 are small algorithmic programs that exercise loops and variadic operators; 11 shows a real DSL package. If you only skim three, make them 03 (arrays and higher-order blocks), 05 (the dynamic-operator trap), and 11 (how jth programs pull in extra vocabularies).

The index with one-line summaries also lives in the repo at examples/README.md.