nix-playgraound/28-haskell-applicative-validation

28-haskell-applicative-validation

This example shows intermediate Haskell validation with an Applicative error accumulator.

It includes:

• a custom Validation type that accumulates multiple errors,
• a release manifest built from validated fields,
• a CLI that reports all invalid fields at once, and
• a test suite run by nix flake check.

Useful commands:

nix develop
cabal run
cabal run -- service=api-gateway env=production owners=platform,security replicas=3 strategy=canary:20 window=22-24
cabal test

nix build
./result/bin/mini-validation service=api-gateway env=production owners=platform,security replicas=3 strategy=canary:20 window=22-24

nix run . -- service=api-gateway env=production owners=platform,security replicas=3 strategy=canary:20 window=22-24
nix flake check