Tidy up overridable scheme type ♻️

lib/types.nix

@@ -43,8 +43,10 @@ in mergeModules [
     name = "static";
     description = "static wallpaper";
     descriptionClass = "noun";
+
     check = value:
       builtins.attrNames value == [ "colors" "image" ];
+
     constructor =
       { image, polarity ? "either" }:
       {
@@ -57,8 +59,10 @@ in mergeModules [
     name = "slideshow";
     description = "slideshow wallpaper";
     descriptionClass = "noun";
+
     check = value:
       builtins.attrNames value == [ "colors" "delay" "image" "images" ];
+
     constructor =
       { images, delay ? 300, polarity ? "either" }:
       rec {
@@ -72,8 +76,10 @@ in mergeModules [
     name = "animation";
     description = "animated wallpaper";
     descriptionClass = "noun";
+
     check = value:
       builtins.attrNames value == [ "animation" "colors" "image" ];
+
     constructor =
       { animation, polarity ? "either" }:
       rec {
@@ -87,8 +93,10 @@ in mergeModules [
     name = "video";
     description = "video wallpaper";
     descriptionClass = "noun";
+
     check = value:
       builtins.attrNames value == [ "colors" "image" "video" ];
+
     constructor =
       { video, polarity ? "either" }:
       rec {
@@ -104,74 +112,60 @@ in mergeModules [
       types.oneOf [ static slideshow animation video ];
   }
 
-  (typeModule {
-    name = "scheme";
-    description = "base16 scheme";
-    descriptionClass = "noun";
-    check = value:
-      let
-        bases = [
-          "base00" "base01" "base02" "base03"
-          "base04" "base05" "base06" "base07"
-          "base08" "base09" "base0A" "base0B"
-          "base0C" "base0D" "base0E" "base0F"
-        ];
-        meta = [
-          "scheme" "author" "description" "slug"
-        ];
-        requiredAttrs = bases;
-        allowedAttrs = bases ++ meta;
-      in
-        types.path.check value ||
-        (builtins.isAttrs value
-          && all (a: elem a allowedAttrs) (builtins.attrNames value)
-          && all (a: elem a (builtins.attrNames value)) requiredAttrs
-        );
-  })
+  (let
+    bases = [
+      "base00" "base01" "base02" "base03"
+      "base04" "base05" "base06" "base07"
+      "base08" "base09" "base0A" "base0B"
+      "base0C" "base0D" "base0E" "base0F"
+    ];
+    meta = [
+      "scheme" "author" "description" "slug"
+    ];
 
-  (typeModule {
-    name = "override";
-    description = "override for base16 scheme";
-    descriptionClass = "noun";
-    emptyValue.value = { };
-    check = value:
-      let allowedAttrs = [
-        "base00" "base01" "base02" "base03"
-        "base04" "base05" "base06" "base07"
-        "base08" "base09" "base0A" "base0B"
-        "base0C" "base0D" "base0E" "base0F"
-        "scheme" "author" "description" "slug"
-      ];
-      in builtins.isAttrs value
-        && all (a: elem a allowedAttrs) (builtins.attrNames value);
-  })
+    hasOnlyPermittedAttrs = set:
+      all (a: elem a (bases ++ meta)) (attrNames set);
+
+    hasAllRequiredAttrs = set:
+      all (a: elem a (attrNames set)) bases;
+
+    isSchemeOrOverride = value:
+      types.path.check value ||
+      (builtins.isAttrs value && hasOnlyPermittedAttrs value);
+
+    isScheme = value:
+      types.path.check value ||
+      (builtins.isAttrs value && hasAllRequiredAttrs value);
 
-  (typeModule {
-    name = "overridableScheme";
-    description = "base16 scheme with overrides";
-    descriptionClass = "conjunction";
-    emptyValue.value = { };
-    check = value:
-      config.lib.stylix.types.scheme.check value ||
-      config.lib.stylix.types.override.check value;
     merge = optionName: definitions:
       let
         values = catAttrs "value" definitions;
-        partitioned = partition config.lib.stylix.types.scheme.check values;
-        scheme =
-          if length partitioned.right < 1
+
+        partitioned = partition isScheme values;
+        schemes = partitioned.right;
+        overrides = partitioned.wrong;
+
+        schemeDefinition =
+          if length schemes < 1
           then
-            # If only overrides were provided, try applying them to the option default.
+            # If only overrides were found, try looking at the option default for a scheme.
             if hasAttrByPath (optionName ++ [ "default" ]) options
             then getAttrFromPath (optionName ++ [ "default" ]) options
-            else throw "At least one definition for `${showOption optionName}' must be a whole scheme."
+            else throw "At least one definition for `${showOption optionName}' must contain a whole scheme."
           else
-            if length partitioned.right > 1
-            then throw "Only one definition for `${showOption optionName}' may be a whole scheme."
-            else elemAt partitioned.right 0;
-      in foldr
-        (o: s: s.override o)
-        (base16.mkSchemeAttrs scheme)
-        partitioned.wrong;
+            if length schemes > 1
+            then throw "Only one definition for `${showOption optionName}' may contain a whole scheme."
+            else elemAt schemes 0;
+
+        scheme = base16.mkSchemeAttrs schemeDefinition;
+
+      in foldr (o: s: s.override o) scheme overrides;
+
+  in typeModule {
+    name = "scheme";
+    description = "base16 scheme";
+    descriptionClass = "noun";
+    check = isSchemeOrOverride;
+    inherit merge;
   })
 ]

stylix/palette.nix

@@ -111,7 +111,7 @@ in {
     };
 
     colors = mkOption {
-      type = config.lib.stylix.types.overridableScheme;
+      type = config.lib.stylix.types.scheme;
       default = config.stylix.wallpaper.colors;
       defaultText = literalMD "generated scheme based on `stylix.wallpaper`";
       description = ''
@@ -127,6 +127,8 @@ in {
           - Anything from `base00` to `base0F`, but not all of them
           - Optionally `scheme`, `author`, `description` or `slug`
 
+        There must be exactly one whole scheme.
+
         Popular files can be imported from
         [`base16-schemes`](https://github.com/tinted-theming/base16-schemes):
 
@@ -137,7 +139,7 @@ in {
         }
         ```
 
-        To choose a scheme and override it from the same place, use `mkMerge`:
+        To choose a scheme and override it from the same file, use `mkMerge`:
 
         ```nix
         { pkgs, lib, ... }: