Language

Examples Tour

A guided reading order through every program in cookbook/. Each entry gives a one-line summary and a link to the file (and to the in-depth doc where one exists).

Reading order

If you are new to Eta, work through the Beginner and Symbolic & Logic sections first. The AAD & Finance and Causal & Portfolio sections build on each other and culminate in portfolio.eta.

Beginner

Example	Topic
`hello.eta`	First program: `module`, `import`, `defun`, recursion
`basics.eta`	Values, bindings, `cond`, records, quoting
`functions.eta`	`defun`, `lambda`, closures, variadics, `letrec`
`higher-order.eta`	`map*`, `filter`, `foldl`, `zip`, `range`
`composition.eta`	`compose`, `flip`, `negate`, manual currying
`recursion.eta`	Fibonacci, deep flatten, Ackermann, Hanoi
`exceptions.eta`	`catch` / `raise`, `dynamic-wind`, structured payloads

Symbolic & Logic

Example	Topic
`boolean-simplifier.eta`	Tree rewriting, De Morgan, fixed-point
`symbolic-diff.eta`	Computer algebra: differentiation + simplification
`unification.eta`	Raw `logic-var`, `==`, `findall`
`logic.eta`	Relations: `parento`, `grandparento`, `membero`
`send-more-money.eta`	Classic CLP(FD) cryptarithm
`nqueens.eta`	N-Queens via CLP

Reference: Logic, CLP(FD), CLP(B).

AAD & Finance

Example	Topic	Walkthrough
`aad.eta`	Reverse-mode AD primer, `grad`	AAD
`european.eta`	Black–Scholes Greeks (1st & 2nd order)	European options
`sabr.eta`	SABR vol surface, Hagan approximation	SABR
`xva.eta`	CVA / FVA sensitivities via AAD	XVA
`xva-wwr/`	Wrong-Way Risk via do-interventions	XVA with WWR

Statistics & ML

Example	Topic
`stats.eta`	Descriptive stats, OLS
`torch.eta`	libtorch tensor / autograd basics
`tests/torch/`	Layer / optimiser smoke tests

Reference: Stats, Torch.

Concurrency

Example	Pattern
`message-passing.eta`	Parent / child via PAIR
`inproc.eta`	`spawn-thread` with closure capture
`worker-pool.eta`	Parallel fan-out
`parallel-map.eta`	Map over a list, one worker per item
`parallel-fib.eta`	Recursive parallel Fibonacci
`monte-carlo.eta`	Embarrassingly parallel π estimation
`scatter-gather.eta`	SURVEYOR / RESPONDENT
`pub-sub.eta`	Topic-filtered PUB / SUB
`echo-server.eta`, `echo-client.eta`	REQ / REP
`distributed-compute.eta`	Cross-machine TCP messaging

Reference: Message Passing, Networking, Network Message Passing, Supervisor.

Causal & Portfolio

Example	Role	Walkthrough
`causal_demo.eta`	Primer: symbolic + causal + CLP + libtorch	Causal
`do-calculus/`	Worked do-calculus identification problems	Causal
`fact-table.eta`	Columnar fact tables for analytics	Fact Table
`portfolio-lp.eta`	LP construction via `std.clpr`	—
`portfolio.eta`	End-to-end causal portfolio engine	Portfolio

Packaging

Example	Topic	Walkthrough
`packaging/end-to-end/`	End-to-end package flow: local library + app path dependency	First App

Notebooks

Notebook	Topic
`notebooks/`	Jupyter examples (xeus-eta kernel)

See Jupyter for kernel installation.