bash: support -- delimeter

- fixes #163

shtab/__init__.py

@@ -397,40 +397,45 @@ def complete_bash(parser, root_prefix=None, preamble="", choice_functions=None):
   local word_index=0
   _set_parser_defaults
   word_index=1
+  local pos_only=0 # "--" delimeter not encountered yet
 
   # determine what arguments are appropriate for the current state
   # of the arg parser
   while [ $word_index -ne $COMP_CWORD ]; do
     local this_word="${COMP_WORDS[$word_index]}"
 
-    if [[ -n $sub_parsers && " ${sub_parsers[@]} " == *" ${this_word} "* ]]; then
-      # valid subcommand: add it to the prefix & reset the current action
-      prefix="${prefix}_$(_shtab_replace_nonword $this_word)"
-      _set_parser_defaults
-    fi
-
-    if [[ " ${current_option_strings[@]} " == *" ${this_word} "* ]]; then
-      # a new action should be acquired (due to recognised option string or
-      # no more input expected from current action);
-      # the next positional action can fill in here
-      _set_new_action $this_word false
-    fi
-
-    if [[ "$current_action_nargs" != "*" ]] && \\
-       [[ "$current_action_nargs" != "+" ]] && \\
-       [[ "$current_action_nargs" != *"..." ]] && \\
-       (( $word_index + 1 - $current_action_args_start_index >= \\
-          $current_action_nargs )); then
-      $current_action_is_positional && let "completed_positional_actions += 1"
-      _set_new_action "pos_${completed_positional_actions}" true
+    if [[ $pos_only = 1 || " $this_word " != " -- " ]]; then
+      if [[ -n $sub_parsers && " ${sub_parsers[@]} " == *" ${this_word} "* ]]; then
+        # valid subcommand: add it to the prefix & reset the current action
+        prefix="${prefix}_$(_shtab_replace_nonword $this_word)"
+        _set_parser_defaults
+      fi
+
+      if [[ " ${current_option_strings[@]} " == *" ${this_word} "* ]]; then
+        # a new action should be acquired (due to recognised option string or
+        # no more input expected from current action);
+        # the next positional action can fill in here
+        _set_new_action $this_word false
+      fi
+
+      if [[ "$current_action_nargs" != "*" ]] && \\
+         [[ "$current_action_nargs" != "+" ]] && \\
+         [[ "$current_action_nargs" != *"..." ]] && \\
+         (( $word_index + 1 - $current_action_args_start_index >= \\
+            $current_action_nargs + $pos_only )); then
+        $current_action_is_positional && let "completed_positional_actions += 1"
+        _set_new_action "pos_${completed_positional_actions}" true
+      fi
+    else
+      pos_only=1 # "--" delimeter encountered
     fi
 
     let "word_index+=1"
   done
 
   # Generate the completions
 
-  if [[ "${completing_word}" == -* ]]; then
+  if [[ $pos_only = 0 && "${completing_word}" == -* ]]; then
     # optional argument started: use option strings
     COMPREPLY=( $(compgen -W "${current_option_strings[*]}" -- "${completing_word}") )
   else