Add fish prompt function

nixos-config/home-manager.nix

@@ -34,6 +34,45 @@ in
       shellAliases = {
         wget = "wget -c";
       };
+      functions = {
+        fish_prompt = ''
+# Defined in /home/marc/.config/fish/functions/fish_prompt.fish @ line 2
+# slightly modified from defaults
+    set -l last_pipestatus $pipestatus
+    set -lx __fish_last_status $status # Export for __fish_print_pipestatus.
+    set -l normal (set_color normal)
+
+    # Color the prompt differently when we're root
+    set -l color_cwd $fish_color_cwd
+    set -l suffix '>'
+    #if functions -q fish_is_root_user; and fish_is_root_user
+    #    if set -q fish_color_cwd_root
+    #        set color_cwd $fish_color_cwd_root
+    #    end
+    #    set suffix '#'
+    #end
+
+    # If we're running via SSH, change the host color.
+    set -l color_host $fish_color_host
+    #if set -q SSH_TTY
+    #    set color_host $fish_color_host_remote
+    #end
+
+    # Write pipestatus
+    # If the status was carried over (e.g. after `set`), don't bold it.
+    set -l bold_flag --bold
+    set -q __fish_prompt_status_generation; or set -g __fish_prompt_status_generation $status_generation
+    if test $__fish_prompt_status_generation = $status_generation
+        set bold_flag
+    end
+    set __fish_prompt_status_generation $status_generation
+    set -l prompt_status (__fish_print_pipestatus "[" "]" "|" (set_color $fish_color_status) (set_color $bold_flag $fish_color_status) $last_pipestatus)
+
+    echo -n -s (set_color $fish_color_user) "$USER" $normal (set_color $fish_color_separator) @ $normal (set_color $color_host) (prompt_hostname) $normal ' ' (set_color $color_cwd) (prompt_pwd) $normal (fish_vcs_prompt) $normal " "$prompt_status $suffix " "
+    #echo -n -s (set_color --bold red) "$USER" $normal (set_color --bold yellow) @ $normal (set_color cyan) (prompt_hostname) $normal ' ' (set_color yellow) (prompt_pwd) $normal (fish_vcs_prompt) $normal " "$prompt_status $suffix " "
+end
+'';
+      };
     };
   };
 }