41 lines
912 B
Markdown
41 lines
912 B
Markdown
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# Dev Shell versus shellFor
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This note covers `19-devshell-vs-shellfor/`, which builds one local package and exposes two dev shells around it.
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---
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## 1. What Is Being Compared
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The example defines:
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- `devShells.<system>.generic`, built with `pkgs.mkShell`, and
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- `devShells.<system>.shellFor`, built with `haskellPackages.shellFor`.
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Both shells support the same local package, but they are assembled differently.
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---
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## 2. Why the Difference Matters
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`mkShell` is generic. You list tools directly.
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`shellFor` is package-set-aware. It starts from Haskell packages and builds a shell around their dependencies.
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That makes `shellFor` more tightly coupled to the package graph, while `mkShell` stays more explicit and general-purpose.
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---
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## 3. Commands to Try
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```bash
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cd 19-devshell-vs-shellfor
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nix develop .#generic
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nix develop .#shellFor
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nix build
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./result/bin/mini-shell-choice
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nix flake check
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```
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