Optional ReadonlyargumentThe current argument fragment being completed, if any. This is relevant if an argument is composed of multiple parts (e.g. comma-separated lists).
ReadonlycompletionsThe possible completions for the current argument
Optional ReadonlyhintsDisplay-only suggestions (e.g. a <string> type placeholder): previewed as a ghost hint but never inserted on Tab.
Optional ReadonlylabelsWhat Tab displays per completion, only used while several remain: readline inserts what it displays.
Optional ReadonlypreThe completer already selected these, so they must not be filtered against the typed fragment again. Needed when a completion legitimately shares no prefix with what was typed, e.g. a glob expanding to the keys it matches.
Completion suggestions for a specific REPL command