bash completion (it works!)

etc/bash-completion.d/ros

@@ -11,11 +11,45 @@ _ros()
     COMPREPLY=()
     cur="${COMP_WORDS[COMP_CWORD]}"
     prev="${COMP_WORDS[COMP_CWORD-1]}"
-    opts="--help --verbose --version"
 
-    if [[ ${cur} == -* ]] ; then
-        COMPREPLY=( $(compgen -W "${opts}" -- ${cur}) )
-        return 0
-    fi
+    opts="--help -w --wrap -m --image -L --lisp -l --load -S
+    --source-registry --load-system -p --package -sp --system-package -e
+    --eval --require -q --quit -r --restart -E --entry -i --init -ip
+    --print -iw --write -F --final -R --rc +R --no-rc -Q --quicklisp +Q
+    --no-quicklisp -v --verbose --quiet --test"
+
+    subcommands="install config setup version help run wait use list init emacs dump delete build"
+    subcommands_caserule=$(echo $subcommands | sed 's/ /|/g')
+    case $prev in
+        # initially thought emacs has some default shell complete, but it turned out it doesnt
+        # therefore the default completion suffices
+        # emacs)
+        #     # in /usr/share/bash-completion/bash_completion
+        #     _command_offset $((COMP_CWORD-1))
+        #     ;;
+        setup|version|init|run|emacs|wait)
+            # these commands provide only the default completion
+            # it takes no arguments and it does some real jobs
+            # or there are no meaningful subsubcommands
+            return 124
+            # default completion
+            ;;
+        build)
+            # complete filenames
+            COMPREPLY=( $(compgen -A file -o filenames -- ${cur}) ) ;;
+        install|config|help|use|list|dump|delete)
+            # espects these commands output completion candidates to the stdout
+            COMPREPLY=( $(compgen -W "$(ros $prev 2> /dev/null)" -- ${cur}) ) ;;
+        *)
+            if [[ $cur == [+-]* ]]
+            then
+                COMPREPLY=( $(compgen -W "${opts}" -- ${cur}) )
+            else
+                COMPREPLY=( $(compgen -W "${subcommands}" -- ${cur}) )
+            fi
+            ;;
+    esac
+    return 0
 }
+
 complete -F _ros ros