nix-playgraound/09-haskell-newtype

09-haskell-newtype

This example shows intermediate Haskell domain modeling with newtype and smart constructors.

It includes:

• newtype wrappers for UserName and Email,
• smart constructors that validate raw input,
• an explicit Either String error path, and
• a test suite run by nix flake check.

Useful commands:

nix develop
cabal run
cabal run -- learner learner@example.com
cabal test

nix build
./result/bin/mini-registration learner learner@example.com

nix run . -- learner learner@example.com
nix flake check