[Help-bash] [completion] Is it possible to auto complete one word into multiple ones?

[Clark Wang]

For example, the foo command has a ``--select all'' option but has no
``-a'' option. I want to define a compspec for foo so when I input ``foo
-a'' and press <TAB> it'll replace ``-a'' with ``--select all''.

I tried modifying COMP_WORDS or COMP_LINE in my completion function but it
did not work. Seems like those COMP_vars are only for reading.

Thoughts?

-clark