doc string of buffer-invisibility-spec

[Drew Adams]

The doc string says:

Invisibility spec of this buffer.
The default is t, which means that text is invisible
if it has a non-nil `invisible' property.
If the value is a list, a text character is invisible if its `invisible'
property is an element in that list.
If an element is a cons cell of the form (PROP . ELLIPSIS),
then characters with property value PROP are invisible,
and they have an ellipsis as well if ELLIPSIS is non-nil.

It does not say anything about the situation where the `invisible'
property is itself a list. The Elisp manual, node Invisible Text
says this, in addition (where ATOM is a member of the
`buffer-invisibility-spec' value):

   A character is invisible if its `invisible' property
   value is ATOM or if it is a list with ATOM as a member.

The last part is what is missing from the doc string; "or if it is a
list with ATOM as a member".

IIUC, this implies, e.g., that if `buffer-invisibility-spec' is (foo
bar toto) and some text has property `invisible' with value (foo bar),
then it will be invisible, as will text with `invisible' value `foo'
and text with value (bar toto titi). The doc string only covers the
case where the value is `foo', `bar', or `toto', not the possible
list-value cases.

It might even be helpful in the manual to explicitly point out an
example such as value (toto titi), where `b-i-s' is, say, (foo toto)
- to show that the value need not be a subset of `b-i-s', that any
non-empty intersection will make the text invisible.


In GNU Emacs 22.1.50.1 (i386-mingw-nt5.1.2600)
 of 2007-05-22 on LENNART-69DE564
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