# 33-haskell-optparse-cli

This example shows intermediate Haskell CLI parsing with `optparse-applicative`.

It includes:

- subcommands for validation and promotion,
- named options, repeated options, and typed numeric parsing,
- a pure parser entry point that the test suite exercises, and
- a test suite run by `nix flake check`.

Useful commands:

```bash
nix develop
cabal run
cabal run -- validate --service api --env production --replicas 3 --track stable
cabal run -- promote --service api --from-tag blue --to-tag green --owner platform --owner security --dry-run
cabal test

nix build
./result/bin/mini-cli validate --service api --env production --replicas 3 --track stable

nix run . -- validate --service api --env production --replicas 3 --track stable
nix flake check
```