Where to wander next

You have met values, functions, algebraic data, structural recursion, closures, quantities, monads, parallel calls, proofs, and ownership-aware arrays. That is a respectable backpack for a first walk.

A few small next projects:

Extend the shape datatype and check several concrete areas.
Write Nat-recursive list helpers before reaching for unsafe recursion.
Parse two inputs with Maybe, then keep printing confined to IO.
State a law for a tiny function and prove it by matching its input.
Inspect Base's quantity-aware container signatures rather than guessing their Haskell equivalents.

Pocket translation guide

Haskell idea	Bend 2 neighbour	Important difference
`f x`	`f(x)`	Python-shaped calls do not imply Python semantics.
`let x = ...`	`x = ...`	Bindings are affine by default.
`data` and constructors	`type ... is Data/Type` and `K{...}`	The kind determines copyability.
`[]`, `h:t`	`Nil{}`, `Con{h, t}`, `h <> t`	`<>` is cons here, not semigroup append.
`\x -> ...`	`x => ...`	Runtime closures may be called at most once.
Polymorphic functions	Erased type/kind parameters	More explicit arguments and fewer inferred types.
Reusing a function argument	A `~` template argument	Compile-time substitution, with closed arguments.
`IO ()` and `do`	`IO(Unit)` and `do IO<Unit>:`	Explicit result annotations and affine handles.
`Maybe` pipelines	`do Maybe<&2, T>:`	Named `bind`/`pure` conventions rather than instance inference.
Recursive definitions	Structural recursion	Termination required; no ordinary mutual recursion.
QuickCheck properties	Laws plus proof definitions	Sampling examples is not proving a universal claim.
Parallel strategies	Binary parallel calls	Balanced work and target/runtime choices matter.
`ST`/mutable arrays	Affine `Array<T>`	Ownership is returned alongside reads.

Keep the official guide, bend guide, and bend base nearby. When an analogy and the compiler disagree, the analogy loses. Even a charming analogy.

Running the whole shelf

After entering the development shell, run all chapter files from the repository root:

for file in src/*.bend; do
  bend "$file" || break
done

For the browser build and its regression tests, use just test. For the original CLI programs, use just check. The browser build copies the numbered chapters unchanged into generated/chapters/ with import-safe names, because the pinned Bend 2.0.37 compiler rejects digit-leading module imports; the source filenames remain unchanged. browser-examples.bend delegates to those chapter functions and compiles to generated/examples.mjs. Build artifacts are ignored by Git.