Attempt to support vscode extensions.

Author: nc6

lib/schema.ncl

@@ -1,5 +1,6 @@
 let nix = import "./nix-interop/nix.ncl" in
 let filegen = import "files.ncl" in
+let vscode = import "vscode.ncl" in
 {
   OrganistShells = {
     dev
@@ -64,4 +65,5 @@ let filegen = import "files.ncl" in
         = {},
     }
     & filegen.Schema
+    & vscode.Schema
 }

lib/vscode.ncl

@@ -0,0 +1,58 @@
+let nix = import "./nix-interop/nix.ncl" in
+let ExtensionFromMarketplace = {
+  publisher | String,
+  name | String,
+  version | String,
+  sha256 | String
+} in
+let VSCodeSchema = {
+  extensions
+  | doc "Extensions to install locally in the workspace"
+  | { _ : ExtensionFromMarketplace }
+  | default = {}
+} in
+let BuiltExtensionDetails = {
+  name | String,
+  path | Dyn
+} in
+let buildExtension : String -> ExtensionFromMarketplace -> BuiltExtensionDetails = fun extName efm =>
+      { name = extName,
+      path = nix.derivation.CallNix & { function = m%"
+          vscode-utils.buildVscodeMarketplaceExtension
+            { mktplcRef =
+              { publisher = "{publisher}";
+                name = "{name}";
+                version = "{version}";
+                sha256="{sha256}";
+              };
+            }
+        "%,
+        args = {
+            publisher = efm.publisher,
+            name = efm.name,
+            version = efm.version,
+            sha256 = efm.sha256
+          }
+      }} | BuiltExtensionDetails in
+let regenerate-vscode | { _ : ExtensionFromMarketplace} -> nix.derivation.Derivation = fun exts =>
+  { name = "regenerate-vscode-exts",
+    content.text = exts
+      |> std.record.to_array
+      |> std.array.map (fun {field = extName, value = ext} => buildExtension extName ext)
+      |> std.array.fold_left
+        ( fun acc elt =>
+          nix-s%"
+            %{acc}
+            ln -s ".vscode/extensions/%{elt.name}" %{elt.path}
+          "%)
+          "",
+  } | nix.builders.ShellApplication
+in {
+  Schema = {
+    vscode | doc m%"
+      VSCode configuration
+      "% | VSCodeSchema | default
+        = {},
+    flake.apps.regenerate-vscode.program = nix-s%"%{regenerate-vscode vscode.extensions}/bin/regenerate-vscode"%,
+  },
+}