bug#32738: 26.1.50; 'read-answer' allows only single characters as short answers

[Eli Zaretskii <eliz@gnu.org>]

This is a feature request.

The new function read-answer allows only single-character short answers,
and formats them with %c in the prompt displayed to the user.  This has
several disadvantages:

  . Function keys cannot be used as short answers.  For example, it
    would be good to be able to use F1 for "help", but it is currently
    impossible.

  . Character events that aren't valid characters, such as C-M-h,
    cannot be used, because %c barfs when it sees a character event
    with modifiers (it doesn't pass the 'characterp' test).

  . Control characters, like C-h, are shown as raw bytes, with their
    special face, thus standing out unnecessarily.

It would be nice if these restrictions could be lifted.

In GNU Emacs 26.1.50 (build 205, i686-pc-mingw32)
 of 2018-09-15 built on HOME-C4E4A596F7
Repository revision: 20ecc5266e1ffb1cff3e31475631b5c76b99e997
Windowing system distributor 'Microsoft Corp.', version 5.1.2600
Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Configured using:
 'configure --prefix=/d/usr --with-wide-int --with-modules
 --enable-checking=yes,glyphs --enable-check-lisp-object-type
 'CFLAGS=-O0 -gdwarf-4 -g3''

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY ACL GNUTLS LIBXML2 ZLIB
TOOLKIT_SCROLL_BARS MODULES THREADS LCMS2

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1255

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-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
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny seq byte-opt gv
bytecomp byte-compile cconv cl-loaddefs cl-lib dired dired-loaddefs
format-spec rfc822 mml easymenu mml-sec password-cache epa derived epg
epg-config gnus-util rmail rmail-loaddefs mm-decode mm-bodies mm-encode
mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047
rfc2045 ietf-drums mm-util mail-prsvr mail-utils elec-pair time-date
mule-util tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel dos-w32 ls-lisp disp-table term/w32-win w32-win
w32-vars term/common-win tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page menu-bar rfn-eshadow isearch timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame 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 charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote threads w32notify w32 lcms2 multi-tty make-network-process
emacs)

Memory information:
((conses 16 102100 11497)
 (symbols 56 21325 1)
 (miscs 48 42 98)
 (strings 16 31711 1931)
 (string-bytes 1 773712)
 (vectors 16 14876)
 (vector-slots 8 505915 15424)
 (floats 8 55 115)
 (intervals 40 279 103)
 (buffers 880 11))