Problems with info (emacs version)

[Luc Teirlinck]

The concrete problem in info I described earlier concerning the `g'
and `m' commands and invisible text have been solved by a recent
change in the info files themselves by Stefan.

Other, some substantially more severe, problems related to the
existence of "secret text" (because for the user not extremely
familiar with both the invisibility and display properties, that is
exactly what it is) in info, remain.

1.  Easiest one to fix:

    (info)Help-M

    which is used in the tutorial, *only* describes menus as they
    appear in the standalone info, not as they appear in the emacs
    version and the two are very different.  A poor newbie, trying to
    use the tutorial to learn the Emacs version of info, will be
    completely confused, not because he is dumb, but because the
    information does not apply.  This one, is, of course, relatively
    easy to fix.

2.  The problem I described earlier with putting point on
    "* echo" (or similar) and doing M-x man.  No colon in the text,
    no colon in the minibuffer prompt, no "invisible text" (just text
    with the display property), but:

    Error in process sentinel: Can't find the echo: manpage

3.  Invisible text suddenly becomes visible when yanked inside an
    Emacs buffer (by default).  Text with the display property does
    not when yanked in an Emacs buffer, but does when yanked into
    other applications.  Try to make sense of that if you do not know
    about the invisibility property, yank-ignored-properties or the
    display property.  (I would guess that most newbies or casual
    users do not know about any of these, let alone about all of them
    and their subtleties.)  Some text appears completely out of
    nowhere when yanking into an Emacs buffer and then suddenly even
    more text appears when yanking it elsewhere.  What is going on?

4.  Both invisible text and text hidden by the display property
    becomes visible when copied to a file.  The casual user has no
    idea what he is copying to file.

5.  Last and definitely worst.  The user copies part of the info
    buffer into an emacs mail buffer for somebody elses information.
    What the receiver receives is not what the sender believes he
    sent.  Granted, the hidden text does not exactly consist of
    obscenities or such (although I did not yet try to read these node
    names backward to get all the Satanic messages), but this is still
    really bad.

There are plenty of other potential problems, but the above five are
representative.

I have no problems with the way outline mode and C-x $ treat invisible
text, the user chooses to make it invisible.  But the presence of
invisible text of any kind should always be made completely clear to
the user.  Otherwise, there is no limit to the problems that can
arise.

Possible solutions:

1.  The most radical solution would be to make all of that text
    visible.  End of all five problems, as well as of all related
    ones.  Also makes the Emacs info look like the standalone one.
    Less to get used to for people who want to use both.

2.  Actually erase the text (in the buffer) instead of making it
    invisible or giving it the display property.

    This might give problems for the `e' command, but editing using
    the `e' command does not seem like a very desirable thing to do
    anyway.

3.  The least radical and probably most acceptable of the three:
    provide a convenient command to toggle between the "emacs view"
    and the "standalone view" by making not only the invisible text
    visible, but also removing the display property.  But, in this
    case, one should make *really* sure that the user knows about the
    invisible text and about the command to make it visible.

Sincerely,

Luc.