Use fish_color_at to decide the colour of the @ (if present) in the prompt

[vext01]

Description

As discussed here, you can't easily change the colour of the @ in the prompt (if present).

This draft proposes a fix.

TODOs:

• Discuss if this is the correct way to do it.
• Update all themes, adding fish_color_at=normal, so that they all render the same if the user doesn't specify.
• Do something similar for any trailing prompt character? (in the linked issue, the user can't change the colour of the >)

[krobelus]

how about

functions -c fish_prompt default_fish_prompt
function fish_prompt
    default_fish_prompt | string replace @ (set_color red)@
end

[vext01]

how about

I guess that's a workaround, but it doesn't allow individual themes to describe their desired colour.

[krobelus]

is there any theme that wants to this to be different than $fish_color_normal?
If not then we can do

diff --git a/share/functions/prompt_login.fish b/share/functions/prompt_login.fish
index 632a462bd..3ec1647fd 100644
--- a/share/functions/prompt_login.fish
+++ b/share/functions/prompt_login.fish
@@ -26,3 +26,3 @@ function prompt_login --description "display user name for the prompt"
 
-    echo -n -s (set_color $fish_color_user) "$USER" (set_color normal) @ (set_color $color_host) (prompt_hostname) (set_color normal)
+    echo -n -s (set_color $fish_color_user) "$USER" (set_color $fish_color_normal) @ (set_color $color_host) (prompt_hostname) (set_color normal)
 end

AFAICT fish_color_normal is used as fallback for syntax highlighting on text that doesn't have a distinguishing role, or for cases where the highlighting for that role has been explicitly disabled (such as set -e fish_color_command ).

I think that's a relatively obvious approach. In future we should also give prompt variables like $fish_color_user the same behavior of falling back to $fish_color_normal if unset.