Is it possible to exclude applications from Flash Focus?

If you are on the git version, you can add a rule like that (edited from https://awesomewm.org/apidoc/declarative_rules/ruled.client.html):

ruled.client.append_rule {
    rule_any    = {
        except_any = {"firefox"}
    },
    properties = {
        custom_do_not_flash_whatever = true,
    },
}

And then check yourself whether you want to run flashed (edited from https://blingcorp.github.io/bling/#/module/flash):

awful.key({modkey}, "Up",
    function()
       awful.client.focus.bydirection("up")
+      if not client.focus.custom_do_not_flash_whatever then
-      bling.module.flash_focus.flashfocus(client.focus)
+          bling.module.flash_focus.flashfocus(client.focus)
+      end
     end, {description = "focus up", group = "client"})

There is no way that involves no code at all and I think there shouldn't be either

BlingCorp / bling

Is it possible to exclude applications from Flash Focus? #204