# 25-haskell-state

This example shows intermediate Haskell planning with `State`.

It includes:

- a planner state that tracks build numbers and rollout waves,
- stateful allocation of per-environment wave numbers,
- a CLI that renders a deployment plan from compact request strings, and
- a test suite run by `nix flake check`.

Useful commands:

```bash
nix develop
cabal run
cabal run -- api:production:3 worker:staging:1 cache:production:2
cabal test

nix build
./result/bin/mini-state-planner api:production:3 worker:staging:1 cache:production:2

nix run . -- api:production:3 worker:staging:1 cache:production:2
nix flake check
```