`i' in Info: get combo index tailored to input

[Drew Adams]

Feature suggestion for `i' in Info - it could be bound to `C-u i':

Display a list (with links) of all index entries that match the user's
input, grouped by index.  This would, in effect, be a combined index
specialized to the user's input.  It would combine the subsets of each
index that match the user input.

For the input `truncate' in the Emacs manual, for instance, you would
see something like this:

 Command Index

 * comint-truncate-buffer
 * toggle-truncate-lines

 Variable Index

 * truncate-lines
 * truncate-partial-width-windows

For some contexts, this would be more convenient than having to cycle
blindly with `,' - seeing only how many other entries there are (not
what they are and what indexes they occur in).

It would also obviate the minor annoyance of sequentially accessing
multiple matching entries that go to the same target, such as the two
entries that match the input `truncate-lines', one from the Variable
Index and the other from the Command Index, and which go to the same
node.  With ordinary `i' and `,', you need to cycle among the matches
to discover this overlap.


[FWIW - In Icicles, you can get this behavior, with the exception that
the entries are not grouped by index.  You use `i' with completion to
get a set of nodes that match your input.  Then you create a virtual
book (a menu) of those nodes.  For the example above, this is what you
get:

 File: toc,  Node: Top,  Up: (dir)

 Virtual Book
 ************

 * Menu:

 * comint-truncate-buffer (emacs)
 * toggle-truncate-lines (emacs)
 * truncate-lines (emacs)
 * truncate-partial-width-windows (emacs)

]