From 0d7d0be37858da7268f67a73e7476fd5083b13d4 Mon Sep 17 00:00:00 2001
From: Sridhar Ratnakumar <3998+srid@users.noreply.github.com>
Date: Sun, 30 Jun 2024 14:39:39 -0400
Subject: [PATCH 1/2] Create 00-initial-proposal.md

---
 rfcs/00-initial-proposal.md | 73 +++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 rfcs/00-initial-proposal.md

diff --git a/rfcs/00-initial-proposal.md b/rfcs/00-initial-proposal.md
new file mode 100644
index 0000000..1a59871
--- /dev/null
+++ b/rfcs/00-initial-proposal.md
@@ -0,0 +1,73 @@
+# Initial Proposal for `flake-parts-cli`
+
+## Background
+
+`flake-parts` modularizes project `flake.nix` ([example](https://github.com/srid/haskell-template/blob/master/flake.nix)) sufficiently enough to make it almost look like YAML, due to the way the module system works. Developers set "options", with config implementation taken care of by upstream modules ([such as these](https://community.flake.parts/modules)).
+
+Can we go one step further and substantially improve the DX by allowing developers to achieve typical Nix uses cases without having to write Nix? 
+
+## Approach
+
+To achieve this, we propose a CLI that takes as input some YAML or TOML (file formats familiar to many people) and "adjust" (if not auto-generate) the top-level `flake.nix`.
+
+## Spec & Implementation
+
+While the details of the spec & implementation are to be worked out, here's a good starting point:
+
+Let's say our CLI generates an initial `flake.nix` with "placeholder" comments:
+
+```nix
+{
+  inputs = {
+    # START inputs managed by flake-parts cli
+    <generate whatever we want here>
+    # END inputs managed by flake-parts cli
+  }:
+  outputs = inputs: inputs.flake-parts.mkFlake {
+    inherit inputs;
+    # A toml file is easier to manage
+    specialArgs.flake-parts-toml = ./nix/flake-parts.toml;
+    modules = [
+       # and this module could translate the toml into module definitions
+      inputs.flake-parts-cli.flakeModule
+    ];
+  };
+}
+```
+
+This flake points to a TOML file that, for a Haskell project, may look like this:
+
+```toml
+# ./nix/flake-parts.toml
+# flake-parts TOML
+
+[flake.registry]
+url = "https://github.com/juspay/flake-registry"
+
+[flake.inputs]
+nixpkgs.url = "nixpkgs"
+haskell-flake.url = "haskell-flake"
+euler-hs.url = "github:juspay/euler-hs"
+euler-hs.follow-auto = ["nixpkgs", "haskell-flake"]
+
+[flake.parts]
+imports = "haskell-flake"
+
+[flake.parts.haskellProjects.default]
+projectRoot = "."
+[flake.parts.haskellProjects.default.settings]
+euler-hs.check = false
+[flake.parts.haskellProjects.default.defaults.settings.local]
+buildFromSdist = false
+haddock = true
+
+[flake.outputs.packages]
+default = "${self'.packages.hello-world}"
+
+[flake.outputs.devShells.default]
+packages = ["${pkgs.haskellPackages.ghcid}", "${pkgs.node}"]
+```
+
+Now, the user can simply edit the TOML file (`./nix/flake-parts.toml`) to make any changes, without writing a line of Nix. The `flake-parts-cli` app will support commands for "adding" or "removing" modules, which automatically will modify the `inputs` part of the flake. Developers can then configure their new modules in the TOML file. The CLI can also wrap the various Nix commands like `build`, `develop` and so forth, whilst even being ambitious enough to provide custom subcommands to be specified by upstream modules (for e.g., [services-flake](https://github.com/juspay/services-flake) can provide custom subcommands to add/remove services).
+
+Developers can write custom modules and have them imported in top-level flake for those (rare) advanced use-cases; thus they don't have to move away from being able to use the full power of Nix.

From 14e4dab502ddb36adb530118ddf27bad27a35e60 Mon Sep 17 00:00:00 2001
From: Sridhar Ratnakumar <3998+srid@users.noreply.github.com>
Date: Sun, 30 Jun 2024 18:10:48 -0400
Subject: [PATCH 2/2] TOML can be manipulated by the CLI

Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
---
 rfcs/00-initial-proposal.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rfcs/00-initial-proposal.md b/rfcs/00-initial-proposal.md
index 1a59871..56b109b 100644
--- a/rfcs/00-initial-proposal.md
+++ b/rfcs/00-initial-proposal.md
@@ -25,7 +25,7 @@ Let's say our CLI generates an initial `flake.nix` with "placeholder" comments:
   }:
   outputs = inputs: inputs.flake-parts.mkFlake {
     inherit inputs;
-    # A toml file is easier to manage
+    # A toml file is easier to manipulate programmatically
     specialArgs.flake-parts-toml = ./nix/flake-parts.toml;
     modules = [
        # and this module could translate the toml into module definitions