bug#57160: 28.1.91; Info Virtual Index fails on search "two column"

bug#57160: 28.1.91; Info Virtual Index fails on search "two column"

[Van Ly]

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Inside Emacs at  the infopage for Emacs, the search  term "two column"
finds   no   result,  the   search   term   "column"  finds   in   the
"Info Virtual Index" the result:

  . 2C-two-columns [Command Index]: Two-Column.

Steps to reproduce

  . start "emacs -Q"
  . open Emacs's infopage by "F1 i" and navigating to entry for Emacs
  . search index using "I" and type "two column"
  . echo area says "No 'two column' in index"

Expected result finds

  . 2C-two-columns [Command Index]: Two-Column.

-- 
vl					     GNU Emacs 27.2 NetBSD 9.3

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In GNU Emacs 28.1.91 (build 1, aarch64-unknown-linux-gnu, GTK+ Version 3.24.24, cairo version 1.16.0)
 of 2022-08-08 built on charlie
Repository revision: 059ab47a0664012b4d8cf8cc36b7d8a28b80c614
Repository branch: main
Windowing system distributor 'The X.Org Foundation', version 11.0.12011000
System Description: Debian GNU/Linux 11 (bullseye)

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
LCMS2 LIBOTF LIBSELINUX LIBSYSTEMD LIBXML2 M17N_FLT MODULES NOTIFY
INOTIFY PDUMPER PNG RSVG SECCOMP SOUND THREADS TIFF TOOLKIT_SCROLL_BARS
X11 XDBE XIM XPM GTK3 ZLIB

Important settings:
  value of $LC_ALL: en_AU.UTF-8
  value of $LANG: en_AU.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Info

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  show-paren-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t
  indent-tabs-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny rfc822 mml mml-sec epa
derived epg rfc6068 epg-config gnus-util rmail rmail-loaddefs
auth-source cl-seq eieio eieio-core cl-macs eieio-loaddefs
password-cache json map text-property-search time-date subr-x seq
byte-opt gv bytecomp byte-compile cconv mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mm-util mail-prsvr mail-utils mule-util info
dired-aux dired dired-loaddefs help-mode cl-loaddefs cl-lib iso-transl
tooltip eldoc paren electric uniquify ediff-hook vc-hooks
lisp-float-type elisp-mode mwheel term/x-win x-win term/common-win x-dnd
tool-bar dnd fontset image regexp-opt fringe tabulated-list replace
newcomment text-mode lisp-mode prog-mode register page tab-bar menu-bar
rfn-eshadow isearch easymenu timer select scroll-bar mouse jit-lock
font-lock syntax font-core term/tty-colors frame minibuffer cl-generic
cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech
european ethiopic indian cyrillic chinese composite emoji-zwj charscript
charprop case-table epa-hook jka-cmpr-hook help simple abbrev obarray
cl-preloaded nadvice button loaddefs faces cus-face macroexp files
window text-properties overlay sha1 md5 base64 format env code-pages
mule custom widget hashtable-print-readable backquote threads dbusbind
inotify lcms2 dynamic-setting system-font-setting font-render-setting
cairo move-toolbar gtk x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 67813 7337)
 (symbols 48 7189 1)
 (strings 32 24705 1831)
 (string-bytes 1 770949)
 (vectors 16 15178)
 (vector-slots 8 215387 14648)
 (floats 8 32 40)
 (intervals 56 970 461)
 (buffers 992 13))

bug#57160: 28.1.91; Info Virtual Index fails on search "two column"

[Juri Linkov]

> Inside Emacs at  the infopage for Emacs, the search  term "two column"
> finds   no   result,  the   search   term   "column"  finds   in   the
> "Info Virtual Index" the result:
>
>  . 2C-two-columns [Command Index]: Two-Column.
>
> Steps to reproduce
>
>  . start "emacs -Q"
>  . open Emacs's infopage by "F1 i" and navigating to entry for Emacs
>  . search index using "I" and type "two column"
>  . echo area says "No 'two column' in index"
>
> Expected result finds
>
>  . 2C-two-columns [Command Index]: Two-Column.

Everything works fine when you type "I two-column".

bug#57160: 28.1.91; Info Virtual Index fails on search "two column"

[Van Ly]

On Fri, 12 Aug 2022, Juri Linkov wrote:

>>
>> Expected result finds
>>
>>  . 2C-two-columns [Command Index]: Two-Column.
>
> Everything works fine when you type "I two-column".
>

Everyday search engines would accept "two column" and add in the hyphen.

-- 
vl
 				 ALPINE 2.24 GNU Emacs 27.2 NetBSD 9.3

bug#57160: 28.1.91; Info Virtual Index fails on search "two column"

[Drew Adams]

> Everyday search engines would accept "two column" and add in the hyphen.

(Not chiming in on whether something should be done in Info.)

Just pointing out that the "everyday search engines" you're thinking of (e.g. PDF searching, web search engines...) typically perform what's called "full-text search" or "indexed search".

They _index_ a set of documents, breaking down words into roots, endings, etc.  So they can match singular/plural and other forms of words that have the same root, and perform other kinds of search (boolean predicates, nearness tests, etc.).

They don't do the kind of searching that Emacs does, in general.  Emacs searching is typically plain-text, and it allows for the use of regexps, for example.

These are two very different search worlds.  Try searching for "two-column" with Google search and not getting hits also for "two column".  Each kind of search has its advantages.  Emacs searching is good for most uses of Emacs.

bug#57160: 28.1.91; Info Virtual Index fails on search "two column"

[Van Ly]

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On Fri, 12 Aug 2022, Drew Adams wrote:

> These  are two  very  different search  worlds.   Try searching  for
> "two-column" with Google  search and not getting hits  also for "two
> column".  Each kind  of search has its  advantages.  Emacs searching
> is good for most uses of Emacs.

There's a book "introduction to information retrieval" by Manning,
Raghavan, Schütze published by CUP for intuition and guidance.

I often use a search engine to locate the infopage on the web and
navigate there by the infopage node structure to read it.

bug#57160: 28.1.91; Info Virtual Index fails on search "two column"

[Eli Zaretskii]

> Cc: 57160@debbugs.gnu.org
> Date: Fri, 12 Aug 2022 18:01:06 +0000 (UTC)
> From: Van Ly <van.ly@sdf.org>
> 
> On Fri, 12 Aug 2022, Juri Linkov wrote:
> 
> >> Expected result finds
> >>
> >>  . 2C-two-columns [Command Index]: Two-Column.
> >
> > Everything works fine when you type "I two-column".
> 
> Everyday search engines would accept "two column" and add in the hyphen.

The usual method with Info is to type "two" and then TAB.

bug#57160: 28.1.91; Info Virtual Index fails on search "two column"

[Van Ly]

On Fri, 12 Aug 2022, Eli Zaretskii wrote:

>> Everyday search engines would accept "two column" and add in the hyphen.
>
> The usual method with Info is to type "two" and then TAB.
>

That's  very  impressive.   Findable  documentation on  using  TAB  in
various context all in one  place adds value overall.  Somewhere after
C-h a TAB  will list all the  key completions.  Since I  modify C-h to
backspace

   (keyboard-translate ?\C-h ?\C-?)

I think TAB isn't availabe after  the F1 equivalent to C-h.  The input
method for chinese-ctlaub uses TAB in the same way.

Possibly unrelated to Emacs, I see the following on invoking 'emacs -Q'

```

% /usr/X/Projects/emacs-28.1.91/src/emacs -Q

(emacs:64490): dbind-WARNING **: 05:03:23.806: AT-SPI: Error retrieving accessibility bus address: org.freedesktop.DBus.Error.ServiceUnknown: The name org.a11y.Bus was not provided by any .service files

```