vanadium: source each environment when needed individually

nix/configurations/vanadium/home/programs.nix

@@ -42,21 +42,8 @@ in {
       programs = {
         neovim.enable = true;
         neovim.defaultEditor = true;
-        fish = {
-          enable = true;
-          shellInitLast = ''
-            if test -d ~/.environments
-              for file in ~/.environments/*
-                if not string match -q --regex -- '-link$' $file
-                  # - global: make sure the path added is scoped to the instance of the shell
-                  #   https://github.com/fish-shell/fish-shell/issues/8604#issuecomment-2854550904
-                  # - append: make my own environment come after a nix shell even if invoked by one
-                  fish_add_path --global --append --move $file/bin
-                end
-              end
-            end
-          '';
-        };
+
+        fish.enable = true;
         starship.enable = true;
         tmux.enable = true;
         direnv.enable = true;

nix/homeModules/common/fish/functions/activate-nix-env.fish

@@ -0,0 +1,11 @@
+function activate-nix-env \
+    --description "Add a nix environment into path"
+    ### Arguments:
+    if [ (count $argv) -ne 1 ]
+        echo "Must provide exactly one argument, the path to be added"
+        return 1
+    end
+    set env_name $argv[1]
+
+    fish_add_path --global "$HOME/.environments/$argv[1]/bin"
+end

nix/homeModules/common/fish/functions/deactivate-nix-env.fish

@@ -0,0 +1,11 @@
+function deactivate-nix-env \
+    --description "Remove a nix environment from path"
+    ### Arguments:
+    if [ (count $argv) -ne 1 ]
+        echo "Must provide exactly one argument, the path to be removed"
+        return 1
+    end
+    set env_name $argv[1]
+
+    fish_remove_path "$HOME/.environments/$argv[1]/bin"
+end