Re: insert-file-contents and format-decode

[martin rudalics]

>     We'd have to distinguish the calls of `format-decode' by
>
>     (1) `insert-file-contents' with `visit-flag' t
>
> In this case, format decoding should make no undo information, just as
> inserting the visited file contents makes no undo information.  A
> newly visited file starts out with no undo information.
>
>     (2) `insert-file-contents' with `visit-flag' nil
>
> This is the case where it is desirable to make just one undo entry for
> the file contents as finally decoded.
>
>     (3) functions within format.el (and maybe other functions)
>
> For this case, they should do nothing special about undo.
> The primitives they call should make undo entries normally.

The problem is that I have to communicate this information in my call to
`format-decode'.  Currently we have no way to distinguish cases (2) and
(3) both have `visit-flag' nil.  Either we set `visit-flag' to some
constant (say `insert-file-contents-non-visit') for case (2) or provide
an additional argument to `format-decode'.