stylix: parametrize and change testbed field separator (#887)

Parametrize and change the testbed field separator to the colon (':')
character to avoid ambiguity with module names containing hyphens ('-'),
and allow testbed names to contain hyphens.

Fixes: 211a8440e7 ("stylix: support multiple testbeds per module (#858)")

README.md

@@ -54,8 +54,8 @@ Photos by [Clay Banks](https://unsplash.com/photos/three-bicycles-parked-in-fron
 and [Derrick Cooper](https://unsplash.com/photos/brown-road-in-forest-during-daytime-L505cPnmIds).
 
 Try a live demo of this theme by running
-`nix run github:danth/stylix#testbed-gnome-default-light` or
-`nix run github:danth/stylix#testbed-gnome-default-dark`.
+`nix run github:danth/stylix#testbed:gnome:default:light` or
+`nix run github:danth/stylix#testbed:gnome:default:dark`.
 
 ### KDE Plasma 5
 

docs/src/testbeds.md

@@ -52,19 +52,19 @@ github:danth/stylix
     └───x86_64-linux
         ├───docs: package 'stylix-book'
         ├───palette-generator: package 'palette-generator'
-        ├───testbed-gnome-default-dark: package 'testbed-gnome-default-dark'
-        ├───testbed-gnome-default-light: package 'testbed-gnome-default-light'
-        ├───testbed-kde-default-dark: package 'testbed-kde-default-dark'
-        └───testbed-kde-default-light: package 'testbed-kde-default-light'
+        ├───testbed:gnome:default:dark: package 'testbed:gnome:default:dark'
+        ├───testbed:gnome:default:light: package 'testbed:gnome:default:light'
+        ├───testbed:kde:default:dark: package 'testbed:kde:default:dark'
+        └───testbed:kde:default:light: package 'testbed:kde:default:light'
 ```
 
 (This has been edited down to only the relevant parts.)
 
 To start a testbed, each of which is named in the format
-`testbed-«module»-«testbed»-«polarity»`, run the following command:
+`testbed:«module»:«testbed»:«polarity»`, run the following command:
 
 ```console
-user@host:~$ nix run .#testbed-«module»-«testbed»-«polarity»
+user@host:~$ nix run .#testbed:«module»:«testbed»:«polarity»
 ```
 
 Any package with a name not fitting the given format is not a testbed,
@@ -74,7 +74,7 @@ Once the virtual machine starts, a window should open, similar to the screenshot
 below. The contents of the virtual machine will vary depending on the target you
 selected earlier.
 
-![GDM login screen with a dark background color and showing a guest user](testbed-gnome-default-dark.png)
+![GDM login screen with a dark background color and showing a guest user](testbed_gnome_default_dark.png)
 
 If the testbed includes a login screen, the guest user should log in
 automatically when selected. Depending on the software used, you may still be

stylix/testbed.nix

@@ -6,6 +6,7 @@
 }:
 
 let
+  testbedFieldSeparator = ":";
   username = "guest";
 
   commonModule =
@@ -114,8 +115,8 @@ let
 
           # To prevent ambiguity with the final derivation's hyphen field
           # separator, testbed names should not contain hyphens.
-          else if lib.hasInfix "-" testbed then
-            builtins.throw "testbed name must not contain hyphens (-): ${testbed}"
+          else if lib.hasInfix testbedFieldSeparator testbed then
+            builtins.throw "testbed name must not contain the '${testbedFieldSeparator}' testbed field separator: ${testbed}"
 
           else
             {
@@ -131,7 +132,12 @@ let
   makeTestbed =
     testbed: stylix:
     let
-      name = "testbed-${testbed.module}-${testbed.name}-${stylix.polarity}";
+      name = builtins.concatStringsSep testbedFieldSeparator [
+        "testbed"
+        testbed.module
+        testbed.name
+        stylix.polarity
+      ];
 
       system = lib.nixosSystem {
         inherit (pkgs) system;