define-command mark-save %{
    try %{
        execute-keys '"jZ'
        echo "Mark saved"
    } catch %{
        info "Couldn't save mark!"
    }
}

define-command mark-restore %{
    try %{
        execute-keys '"jz'
        echo "Mark restored"
    } catch %{
        info "Couldn't restore mark!"
    }
}

map global normal <c-Y> ': mark-save<ret>'
map global normal <c-y> ': mark-restore<ret>'