Re: Substring matching for info index command

[Stefan Monnier <monnier@iro.umontreal.ca>]

> I've never used the builtin completion-styles, because I 
> use other completion packages, but I thought I give it a try
> and try substring matching for the info index command.

Info should setup a "completion category" so you could configure this
via `completion-category-overrides'.  Please M-x report-emacs-bug.

> I added this advice to the command which wraps it in a
> let and sets completion-styles to substring:

> (defadvice Info-index (around my-Info-index activate)
>   (let ((completion-styles '(substring)))
>     ad-do-it))

That affects the body of the function (i.e. the code that, given
a query, will look for the corresponding place in the index), whereas
you want to tweak the way the interactive-spec works.

You might like to try something like (guaranteed 100% untested):

   (advice-add 'Info-index :before
               (lambda (&rest _)
                 (interactive
                   (lambda (spec)
                     (let ((completion-styles '(substring)))
                       (advice-eval-interactive-spec spec))))
                 nil))
                             
-- Stefan