26 lines
547 B
Markdown
26 lines
547 B
Markdown
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# 09-haskell-newtype
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This example shows intermediate Haskell domain modeling with `newtype` and smart constructors.
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It includes:
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- `newtype` wrappers for `UserName` and `Email`,
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- smart constructors that validate raw input,
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- an explicit `Either String` error path, and
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- a test suite run by `nix flake check`.
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Useful commands:
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```bash
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nix develop
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cabal run
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cabal run -- learner learner@example.com
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cabal test
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nix build
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./result/bin/mini-registration learner learner@example.com
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nix run . -- learner learner@example.com
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nix flake check
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```
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