bug#17476: 24.3.91; [PATCH] unimplemented info entry

[Eli Zaretskii <eliz@gnu.org>]

> From: Shigeru Fukaya <shigeru.fukaya@gmail.com>
> Date: Tue, 13 May 2014 00:54:29 +0900
> 
> Emacs info doesn't recognize info file entries without parentheses in
> dir node.  In Cygwin, libc and libm entries in dir are just like:;
> 
> * libc::            The ANSI C library.
> * libm::            An ANSI-C conforming mathematical library.

This is invalid Info.  Please ask Cygwin maintainers to fix that.

> Cygwin info command treat them as info files.

No, it doesn't.  A reference such as 'foo::' is parsed as a _node_
named "foo" in the 'dir' file.  Info then searches for such a node in
the file 'dir', and doesn't find it.  It then falls back on a kludgy
feature, whereby typing "info foo" from the shell prompt looks for a
_file_ 'foo' or 'foo.info', on the assumption that the
bozo^H^H^H^Huser forgot to type -f, as in "info -f foo".

IOW, the above dir file abuses a kludge in the Info reader introduced
to shut up all those who complain because they cannot be bothered to
invoke the reader as prescribed in the documentation.

In any case, this kludge is for invoking the Info reader from the
shell prompt, not for navigating inside Info files.  IOW, this is
actually a buglet in Info, which therefore can disappear without
notice.

> With the attached patch, Emacs regards the above format in a dir node
> as info file names.

This patch is incorrect.  It treats the dir file specially, whereas it
is simply an Info file with a menu, and nothing prevents the Cygwin
maintainers from putting such menu items in any other Info files.
More importantly, it tramps on a useful feature, whereby a reference
such as "foo::" is actually a shortcut for "(dir)foo::".

So I hope we will not accept this change.

But thanks for reporting the problem and for working on it.