# Surface Languages


Surface-language examples build a simply typed lambda calculus in
layers. The core syntax introduces functions and application; later
pages add products, sums, recursive lists, refinements, and diagnostics.

The source for this section lives under [examples/](https://github.com/kleisli-io/nix-effects/tree/main/examples).

## Walkthroughs

- [Surface STLC](/nix-effects/surface-examples/stlc): Surface-language walkthroughs for a simply typed lambda calculus.