From cffc04c48dfed59ab9d958b9b64948d5fa491fbe Mon Sep 17 00:00:00 2001
From: Alexander Gramiak <agrambot@gmail.com>
Date: Wed, 3 Apr 2019 14:03:28 -0600
Subject: [PATCH] Define and use new procedure display-symbol-keys-p
* lisp/frame.el (display-symbol-keys-p): Define.
* lisp/simple.el (normal-erase-is-backspace-setup-frame): Use eq
instead of memq.
(normal-erase-is-backspace-mode): Use display-symbol-keys-p.
---
etc/NEWS | 6 ++++++
lisp/frame.el | 10 ++++++++++
lisp/simple.el | 7 ++++---
3 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/etc/NEWS b/etc/NEWS
index 26c761ae01f..be4543c0166 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1230,6 +1230,12 @@ the 128...255 range, as expected.
This allows to create and parent immediately a minibuffer-only child
frame when making a frame.
+---
+*** New predicates 'display-blink-cursor-p' and 'display-symbol-keys-p'.
+These predicates are to be preferred over 'display-graphic-p' when
+testing for blinking cursor capability and the capability to have
+symbols (e.g., [return], [tab], [backspace]) as keys respectively.
+
** Tabulated List mode
+++
diff --git a/lisp/frame.el b/lisp/frame.el
index cc8ca49b3b7..aa14e87d7b8 100644
--- a/lisp/frame.el
+++ b/lisp/frame.el
@@ -1927,6 +1927,16 @@ frame's display)."
(t
nil))))
+(defun display-symbol-keys-p (&optional display)
+ "Return non-nil if DISPLAY supports symbol names as keys.
+This means that, for example, DISPLAY can differentiate between
+the keybinding RET and [return]."
+ (let ((frame-type (framep-on-display display)))
+ (or (memq frame-type '(x w32 ns pc))
+ ;; MS-DOS and MS-Windows terminals have built-in support for
+ ;; function (symbol) keys
+ (memq system-type '(ms-dos windows-nt)))))
+
(declare-function x-display-screens "xfns.c" (&optional terminal))
(defun display-screens (&optional display)
diff --git a/lisp/simple.el b/lisp/simple.el
index 306df967661..857e0fc001b 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -8690,7 +8690,7 @@ call `normal-erase-is-backspace-mode' (which see) instead."
(and (not noninteractive)
(or (memq system-type '(ms-dos windows-nt))
(memq window-system '(w32 ns))
- (and (memq window-system '(x))
+ (and (eq window-system 'x)
(fboundp 'x-backspace-delete-keys-p)
(x-backspace-delete-keys-p))
;; If the terminal Emacs is running on has erase char
@@ -8701,6 +8701,8 @@ call `normal-erase-is-backspace-mode' (which see) instead."
normal-erase-is-backspace)
1 0)))))
+(declare-function display-symbol-keys-p "frame" (&optional display))
+
(define-minor-mode normal-erase-is-backspace-mode
"Toggle the Erase and Delete mode of the Backspace and Delete keys.
@@ -8736,8 +8738,7 @@ See also `normal-erase-is-backspace'."
(let ((enabled (eq 1 (terminal-parameter
nil 'normal-erase-is-backspace))))
- (cond ((or (memq window-system '(x w32 ns pc))
- (memq system-type '(ms-dos windows-nt)))
+ (cond ((display-symbol-keys-p)
(let ((bindings
'(([M-delete] [M-backspace])
([C-M-delete] [C-M-backspace])
--
2.39.5